diff options
| author | Ingo Molnar <mingo@kernel.org> | 2025-05-25 10:10:08 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-05-25 10:10:08 +0200 |
| commit | 94ec70880fd376dd5cc60ba2bd7ddf830b3d4f28 (patch) | |
| tree | f0cb51c5eeadc2927c648b49c713f10809db5fd5 | |
| parent | cdb7d2d68cde6145a06a56c9d5d5d917297501c6 (diff) | |
| parent | 78272d44970c07899c78661f6b7492b5a7e14a90 (diff) | |
| download | ipsec-94ec70880fd376dd5cc60ba2bd7ddf830b3d4f28.tar.gz | |
Merge branch 'locking/futex' into locking/core, to pick up pending futex changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
35 files changed, 2479 insertions, 564 deletions
diff --git a/include/linux/futex.h b/include/linux/futex.h index b70df27d7e85c2..005b040c4791bb 100644 --- a/include/linux/futex.h +++ b/include/linux/futex.h @@ -4,11 +4,11 @@ #include <linux/sched.h> #include <linux/ktime.h> +#include <linux/mm_types.h> #include <uapi/linux/futex.h> struct inode; -struct mm_struct; struct task_struct; /* @@ -34,6 +34,7 @@ union futex_key { u64 i_seq; unsigned long pgoff; unsigned int offset; + /* unsigned int node; */ } shared; struct { union { @@ -42,11 +43,13 @@ union futex_key { }; unsigned long address; unsigned int offset; + /* unsigned int node; */ } private; struct { u64 ptr; unsigned long word; unsigned int offset; + unsigned int node; /* NOT hashed! */ } both; }; @@ -77,7 +80,25 @@ void futex_exec_release(struct task_struct *tsk); long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, u32 __user *uaddr2, u32 val2, u32 val3); -#else +int futex_hash_prctl(unsigned long arg2, unsigned long arg3, unsigned long arg4); + +#ifdef CONFIG_FUTEX_PRIVATE_HASH +int futex_hash_allocate_default(void); +void futex_hash_free(struct mm_struct *mm); + +static inline void futex_mm_init(struct mm_struct *mm) +{ + RCU_INIT_POINTER(mm->futex_phash, NULL); + mutex_init(&mm->futex_hash_lock); +} + +#else /* !CONFIG_FUTEX_PRIVATE_HASH */ +static inline int futex_hash_allocate_default(void) { return 0; } +static inline void futex_hash_free(struct mm_struct *mm) { } +static inline void futex_mm_init(struct mm_struct *mm) { } +#endif /* CONFIG_FUTEX_PRIVATE_HASH */ + +#else /* !CONFIG_FUTEX */ static inline void futex_init_task(struct task_struct *tsk) { } static inline void futex_exit_recursive(struct task_struct *tsk) { } static inline void futex_exit_release(struct task_struct *tsk) { } @@ -88,6 +109,17 @@ static inline long do_futex(u32 __user *uaddr, int op, u32 val, { return -EINVAL; } +static inline int futex_hash_prctl(unsigned long arg2, unsigned long arg3, unsigned long arg4) +{ + return -EINVAL; +} +static inline int futex_hash_allocate_default(void) +{ + return 0; +} +static inline void futex_hash_free(struct mm_struct *mm) { } +static inline void futex_mm_init(struct mm_struct *mm) { } + #endif #endif diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 56d07edd01f914..32ba5126e2214b 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -31,6 +31,7 @@ #define INIT_PASID 0 struct address_space; +struct futex_private_hash; struct mem_cgroup; /* @@ -1031,7 +1032,11 @@ struct mm_struct { */ seqcount_t mm_lock_seq; #endif - +#ifdef CONFIG_FUTEX_PRIVATE_HASH + struct mutex futex_hash_lock; + struct futex_private_hash __rcu *futex_phash; + struct futex_private_hash *futex_phash_new; +#endif unsigned long hiwater_rss; /* High-watermark of RSS usage */ unsigned long hiwater_vm; /* High-water virtual memory usage */ diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h index 4706c676990275..e0eddfd306ef3b 100644 --- a/include/linux/mmap_lock.h +++ b/include/linux/mmap_lock.h @@ -7,6 +7,7 @@ #include <linux/rwsem.h> #include <linux/tracepoint-defs.h> #include <linux/types.h> +#include <linux/cleanup.h> #define MMAP_LOCK_INITIALIZER(name) \ .mmap_lock = __RWSEM_INITIALIZER((name).mmap_lock), @@ -211,6 +212,9 @@ static inline void mmap_read_unlock(struct mm_struct *mm) up_read(&mm->mmap_lock); } +DEFINE_GUARD(mmap_read_lock, struct mm_struct *, + mmap_read_lock(_T), mmap_read_unlock(_T)) + static inline void mmap_read_unlock_non_owner(struct mm_struct *mm) { __mmap_lock_trace_released(mm, false); diff --git a/include/linux/rcuref.h b/include/linux/rcuref.h index 6322d8c1c6b429..2fb2af6d982497 100644 --- a/include/linux/rcuref.h +++ b/include/linux/rcuref.h @@ -30,7 +30,11 @@ static inline void rcuref_init(rcuref_t *ref, unsigned int cnt) * rcuref_read - Read the number of held reference counts of a rcuref * @ref: Pointer to the reference count * - * Return: The number of held references (0 ... N) + * Return: The number of held references (0 ... N). The value 0 does not + * indicate that it is safe to schedule the object, protected by this reference + * counter, for deconstruction. + * If you want to know if the reference counter has been marked DEAD (as + * signaled by rcuref_put()) please use rcuread_is_dead(). */ static inline unsigned int rcuref_read(rcuref_t *ref) { @@ -40,6 +44,22 @@ static inline unsigned int rcuref_read(rcuref_t *ref) return c >= RCUREF_RELEASED ? 0 : c + 1; } +/** + * rcuref_is_dead - Check if the rcuref has been already marked dead + * @ref: Pointer to the reference count + * + * Return: True if the object has been marked DEAD. This signals that a previous + * invocation of rcuref_put() returned true on this reference counter meaning + * the protected object can safely be scheduled for deconstruction. + * Otherwise, returns false. + */ +static inline bool rcuref_is_dead(rcuref_t *ref) +{ + unsigned int c = atomic_read(&ref->refcnt); + + return (c >= RCUREF_RELEASED) && (c < RCUREF_NOREF); +} + extern __must_check bool rcuref_get_slowpath(rcuref_t *ref); /** diff --git a/include/linux/restart_block.h b/include/linux/restart_block.h index 13f17676c5f49d..7e50bbc94e476c 100644 --- a/include/linux/restart_block.h +++ b/include/linux/restart_block.h @@ -26,7 +26,7 @@ struct restart_block { unsigned long arch_data; long (*fn)(struct restart_block *); union { - /* For futex_wait and futex_wait_requeue_pi */ + /* For futex_wait() */ struct { u32 __user *uaddr; u32 val; diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 31e9ffd936e393..de95794777ad6b 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -168,8 +168,13 @@ void *__vmalloc_node_noprof(unsigned long size, unsigned long align, gfp_t gfp_m int node, const void *caller) __alloc_size(1); #define __vmalloc_node(...) alloc_hooks(__vmalloc_node_noprof(__VA_ARGS__)) -void *vmalloc_huge_noprof(unsigned long size, gfp_t gfp_mask) __alloc_size(1); -#define vmalloc_huge(...) alloc_hooks(vmalloc_huge_noprof(__VA_ARGS__)) +void *vmalloc_huge_node_noprof(unsigned long size, gfp_t gfp_mask, int node) __alloc_size(1); +#define vmalloc_huge_node(...) alloc_hooks(vmalloc_huge_node_noprof(__VA_ARGS__)) + +static inline void *vmalloc_huge(unsigned long size, gfp_t gfp_mask) +{ + return vmalloc_huge_node(size, gfp_mask, NUMA_NO_NODE); +} extern void *__vmalloc_array_noprof(size_t n, size_t size, gfp_t flags) __alloc_size(1, 2); #define __vmalloc_array(...) alloc_hooks(__vmalloc_array_noprof(__VA_ARGS__)) diff --git a/include/uapi/linux/futex.h b/include/uapi/linux/futex.h index d2ee625ea18900..7e2744ec89336a 100644 --- a/include/uapi/linux/futex.h +++ b/include/uapi/linux/futex.h @@ -63,7 +63,7 @@ #define FUTEX2_SIZE_U32 0x02 #define FUTEX2_SIZE_U64 0x03 #define FUTEX2_NUMA 0x04 - /* 0x08 */ +#define FUTEX2_MPOL 0x08 /* 0x10 */ /* 0x20 */ /* 0x40 */ @@ -75,6 +75,13 @@ #define FUTEX_32 FUTEX2_SIZE_U32 /* historical accident :-( */ /* + * When FUTEX2_NUMA doubles the futex word, the second word is a node value. + * The special value -1 indicates no-node. This is the same value as + * NUMA_NO_NODE, except that value is not ABI, this is. + */ +#define FUTEX_NO_NODE (-1) + +/* * Max numbers of elements in a futex_waitv array */ #define FUTEX_WAITV_MAX 128 diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 15c18ef4eb11a0..43dec6eed559a6 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -364,4 +364,11 @@ struct prctl_mm_map { # define PR_TIMER_CREATE_RESTORE_IDS_ON 1 # define PR_TIMER_CREATE_RESTORE_IDS_GET 2 +/* FUTEX hash management */ +#define PR_FUTEX_HASH 78 +# define PR_FUTEX_HASH_SET_SLOTS 1 +# define FH_FLAG_IMMUTABLE (1ULL << 0) +# define PR_FUTEX_HASH_GET_SLOTS 2 +# define PR_FUTEX_HASH_GET_IMMUTABLE 3 + #endif /* _LINUX_PRCTL_H */ diff --git a/init/Kconfig b/init/Kconfig index 63f5974b9fa6ea..b373267ba2e2b6 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1699,6 +1699,16 @@ config FUTEX_PI depends on FUTEX && RT_MUTEXES default y +config FUTEX_PRIVATE_HASH + bool + depends on FUTEX && !BASE_SMALL && MMU + default y + +config FUTEX_MPOL + bool + depends on FUTEX && NUMA + default y + config EPOLL bool "Enable eventpoll support" if EXPERT default y diff --git a/io_uring/futex.c b/io_uring/futex.c index 0ea4820cd8ff8c..e89c0897117ae5 100644 --- a/io_uring/futex.c +++ b/io_uring/futex.c @@ -273,7 +273,6 @@ int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags) struct io_futex *iof = io_kiocb_to_cmd(req, struct io_futex); struct io_ring_ctx *ctx = req->ctx; struct io_futex_data *ifd = NULL; - struct futex_hash_bucket *hb; int ret; if (!iof->futex_mask) { @@ -295,12 +294,11 @@ int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags) ifd->req = req; ret = futex_wait_setup(iof->uaddr, iof->futex_val, iof->futex_flags, - &ifd->q, &hb); + &ifd->q, NULL, NULL); if (!ret) { hlist_add_head(&req->hash_node, &ctx->futex_list); io_ring_submit_unlock(ctx, issue_flags); - futex_queue(&ifd->q, hb, NULL); return IOU_ISSUE_SKIP_COMPLETE; } diff --git a/kernel/fork.c b/kernel/fork.c index c4b26cd8998b8e..1f5d8083eeb25d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1305,6 +1305,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, RCU_INIT_POINTER(mm->exe_file, NULL); mmu_notifier_subscriptions_init(mm); init_tlb_flush_pending(mm); + futex_mm_init(mm); #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLOCKS) mm->pmd_huge_pte = NULL; #endif @@ -1387,6 +1388,7 @@ static inline void __mmput(struct mm_struct *mm) if (mm->binfmt) module_put(mm->binfmt->module); lru_gen_del_mm(mm); + futex_hash_free(mm); mmdrop(mm); } @@ -2162,6 +2164,13 @@ static void rv_task_fork(struct task_struct *p) #define rv_task_fork(p) do {} while (0) #endif +static bool need_futex_hash_allocate_default(u64 clone_flags) +{ + if ((clone_flags & (CLONE_THREAD | CLONE_VM)) != (CLONE_THREAD | CLONE_VM)) + return false; + return true; +} + /* * This creates a new process as a copy of the old one, * but does not actually start it yet. @@ -2543,6 +2552,21 @@ __latent_entropy struct task_struct *copy_process( goto bad_fork_cancel_cgroup; /* + * Allocate a default futex hash for the user process once the first + * thread spawns. + */ + if (need_futex_hash_allocate_default(clone_flags)) { + retval = futex_hash_allocate_default(); + if (retval) + goto bad_fork_core_free; + /* + * If we fail beyond this point we don't free the allocated + * futex hash map. We assume that another thread will be created + * and makes use of it. The hash map will be freed once the main + * thread terminates. + */ + } + /* * From this point on we must avoid any synchronous user-space * communication until we take the tasklist-lock. In particular, we do * not want user-space to be able to predict the process start-time by diff --git a/kernel/futex/core.c b/kernel/futex/core.c index cca15859a50bef..19a2c65f3d373c 100644 --- a/kernel/futex/core.c +++ b/kernel/futex/core.c @@ -36,9 +36,15 @@ #include <linux/pagemap.h> #include <linux/debugfs.h> #include <linux/plist.h> +#include <linux/gfp.h> +#include <linux/vmalloc.h> #include <linux/memblock.h> #include <linux/fault-inject.h> #include <linux/slab.h> +#include <linux/prctl.h> +#include <linux/rcuref.h> +#include <linux/mempolicy.h> +#include <linux/mmap_lock.h> #include "futex.h" #include "../locking/rtmutex_common.h" @@ -49,12 +55,24 @@ * reside in the same cacheline. */ static struct { - struct futex_hash_bucket *queues; unsigned long hashmask; + unsigned int hashshift; + struct futex_hash_bucket *queues[MAX_NUMNODES]; } __futex_data __read_mostly __aligned(2*sizeof(long)); -#define futex_queues (__futex_data.queues) -#define futex_hashmask (__futex_data.hashmask) +#define futex_hashmask (__futex_data.hashmask) +#define futex_hashshift (__futex_data.hashshift) +#define futex_queues (__futex_data.queues) + +struct futex_private_hash { + rcuref_t users; + unsigned int hash_mask; + struct rcu_head rcu; + void *mm; + bool custom; + bool immutable; + struct futex_hash_bucket queues[]; +}; /* * Fault injections for futexes. @@ -107,21 +125,328 @@ late_initcall(fail_futex_debugfs); #endif /* CONFIG_FAIL_FUTEX */ +static struct futex_hash_bucket * +__futex_hash(union futex_key *key, struct futex_private_hash *fph); + +#ifdef CONFIG_FUTEX_PRIVATE_HASH +static inline bool futex_key_is_private(union futex_key *key) +{ + /* + * Relies on get_futex_key() to set either bit for shared + * futexes -- see comment with union futex_key. + */ + return !(key->both.offset & (FUT_OFF_INODE | FUT_OFF_MMSHARED)); +} + +bool futex_private_hash_get(struct futex_private_hash *fph) +{ + if (fph->immutable) + return true; + return rcuref_get(&fph->users); +} + +void futex_private_hash_put(struct futex_private_hash *fph) +{ + /* Ignore return value, last put is verified via rcuref_is_dead() */ + if (fph->immutable) + return; + if (rcuref_put(&fph->users)) + wake_up_var(fph->mm); +} + /** - * futex_hash - Return the hash bucket in the global hash - * @key: Pointer to the futex key for which the hash is calculated + * futex_hash_get - Get an additional reference for the local hash. + * @hb: ptr to the private local hash. * - * We hash on the keys returned from get_futex_key (see below) and return the - * corresponding hash bucket in the global hash. + * Obtain an additional reference for the already obtained hash bucket. The + * caller must already own an reference. */ +void futex_hash_get(struct futex_hash_bucket *hb) +{ + struct futex_private_hash *fph = hb->priv; + + if (!fph) + return; + WARN_ON_ONCE(!futex_private_hash_get(fph)); +} + +void futex_hash_put(struct futex_hash_bucket *hb) +{ + struct futex_private_hash *fph = hb->priv; + + if (!fph) + return; + futex_private_hash_put(fph); +} + +static struct futex_hash_bucket * +__futex_hash_private(union futex_key *key, struct futex_private_hash *fph) +{ + u32 hash; + + if (!futex_key_is_private(key)) + return NULL; + + if (!fph) + fph = rcu_dereference(key->private.mm->futex_phash); + if (!fph || !fph->hash_mask) + return NULL; + + hash = jhash2((void *)&key->private.address, + sizeof(key->private.address) / 4, + key->both.offset); + return &fph->queues[hash & fph->hash_mask]; +} + +static void futex_rehash_private(struct futex_private_hash *old, + struct futex_private_hash *new) +{ + struct futex_hash_bucket *hb_old, *hb_new; + unsigned int slots = old->hash_mask + 1; + unsigned int i; + + for (i = 0; i < slots; i++) { + struct futex_q *this, *tmp; + + hb_old = &old->queues[i]; + + spin_lock(&hb_old->lock); + plist_for_each_entry_safe(this, tmp, &hb_old->chain, list) { + + plist_del(&this->list, &hb_old->chain); + futex_hb_waiters_dec(hb_old); + + WARN_ON_ONCE(this->lock_ptr != &hb_old->lock); + + hb_new = __futex_hash(&this->key, new); + futex_hb_waiters_inc(hb_new); + /* + * The new pointer isn't published yet but an already + * moved user can be unqueued due to timeout or signal. + */ + spin_lock_nested(&hb_new->lock, SINGLE_DEPTH_NESTING); + plist_add(&this->list, &hb_new->chain); + this->lock_ptr = &hb_new->lock; + spin_unlock(&hb_new->lock); + } + spin_unlock(&hb_old->lock); + } +} + +static bool __futex_pivot_hash(struct mm_struct *mm, + struct futex_private_hash *new) +{ + struct futex_private_hash *fph; + + WARN_ON_ONCE(mm->futex_phash_new); + + fph = rcu_dereference_protected(mm->futex_phash, + lockdep_is_held(&mm->futex_hash_lock)); + if (fph) { + if (!rcuref_is_dead(&fph->users)) { + mm->futex_phash_new = new; + return false; + } + + futex_rehash_private(fph, new); + } + rcu_assign_pointer(mm->futex_phash, new); + kvfree_rcu(fph, rcu); + return true; +} + +static void futex_pivot_hash(struct mm_struct *mm) +{ + scoped_guard(mutex, &mm->futex_hash_lock) { + struct futex_private_hash *fph; + + fph = mm->futex_phash_new; + if (fph) { + mm->futex_phash_new = NULL; + __futex_pivot_hash(mm, fph); + } + } +} + +struct futex_private_hash *futex_private_hash(void) +{ + struct mm_struct *mm = current->mm; + /* + * Ideally we don't loop. If there is a replacement in progress + * then a new private hash is already prepared and a reference can't be + * obtained once the last user dropped it's. + * In that case we block on mm_struct::futex_hash_lock and either have + * to perform the replacement or wait while someone else is doing the + * job. Eitherway, on the second iteration we acquire a reference on the + * new private hash or loop again because a new replacement has been + * requested. + */ +again: + scoped_guard(rcu) { + struct futex_private_hash *fph; + + fph = rcu_dereference(mm->futex_phash); + if (!fph) + return NULL; + + if (fph->immutable) + return fph; + if (rcuref_get(&fph->users)) + return fph; + } + futex_pivot_hash(mm); + goto again; +} + struct futex_hash_bucket *futex_hash(union futex_key *key) { - u32 hash = jhash2((u32 *)key, offsetof(typeof(*key), both.offset) / 4, - key->both.offset); + struct futex_private_hash *fph; + struct futex_hash_bucket *hb; + +again: + scoped_guard(rcu) { + hb = __futex_hash(key, NULL); + fph = hb->priv; + + if (!fph || futex_private_hash_get(fph)) + return hb; + } + futex_pivot_hash(key->private.mm); + goto again; +} + +#else /* !CONFIG_FUTEX_PRIVATE_HASH */ + +static struct futex_hash_bucket * +__futex_hash_private(union futex_key *key, struct futex_private_hash *fph) +{ + return NULL; +} + +struct futex_hash_bucket *futex_hash(union futex_key *key) +{ + return __futex_hash(key, NULL); +} + +#endif /* CONFIG_FUTEX_PRIVATE_HASH */ + +#ifdef CONFIG_FUTEX_MPOL + +static int __futex_key_to_node(struct mm_struct *mm, unsigned long addr) +{ + struct vm_area_struct *vma = vma_lookup(mm, addr); + struct mempolicy *mpol; + int node = FUTEX_NO_NODE; + + if (!vma) + return FUTEX_NO_NODE; + + mpol = vma_policy(vma); + if (!mpol) + return FUTEX_NO_NODE; + + switch (mpol->mode) { + case MPOL_PREFERRED: + node = first_node(mpol->nodes); + break; + case MPOL_PREFERRED_MANY: + case MPOL_BIND: + if (mpol->home_node != NUMA_NO_NODE) + node = mpol->home_node; + break; + default: + break; + } + + return node; +} + +static int futex_key_to_node_opt(struct mm_struct *mm, unsigned long addr) +{ + int seq, node; + + guard(rcu)(); + + if (!mmap_lock_speculate_try_begin(mm, &seq)) + return -EBUSY; + + node = __futex_key_to_node(mm, addr); + + if (mmap_lock_speculate_retry(mm, seq)) + return -EAGAIN; + + return node; +} + +static int futex_mpol(struct mm_struct *mm, unsigned long addr) +{ + int node; + + node = futex_key_to_node_opt(mm, addr); + if (node >= FUTEX_NO_NODE) + return node; - return &futex_queues[hash & futex_hashmask]; + guard(mmap_read_lock)(mm); + return __futex_key_to_node(mm, addr); } +#else /* !CONFIG_FUTEX_MPOL */ + +static int futex_mpol(struct mm_struct *mm, unsigned long addr) +{ + return FUTEX_NO_NODE; +} + +#endif /* CONFIG_FUTEX_MPOL */ + +/** + * __futex_hash - Return the hash bucket + * @key: Pointer to the futex key for which the hash is calculated + * @fph: Pointer to private hash if known + * + * We hash on the keys returned from get_futex_key (see below) and return the + * corresponding hash bucket. + * If the FUTEX is PROCESS_PRIVATE then a per-process hash bucket (from the + * private hash) is returned if existing. Otherwise a hash bucket from the + * global hash is returned. + */ +static struct futex_hash_bucket * +__futex_hash(union futex_key *key, struct futex_private_hash *fph) +{ + int node = key->both.node; + u32 hash; + + if (node == FUTEX_NO_NODE) { + struct futex_hash_bucket *hb; + + hb = __futex_hash_private(key, fph); + if (hb) + return hb; + } + + hash = jhash2((u32 *)key, + offsetof(typeof(*key), both.offset) / sizeof(u32), + key->both.offset); + + if (node == FUTEX_NO_NODE) { + /* + * In case of !FLAGS_NUMA, use some unused hash bits to pick a + * node -- this ensures regular futexes are interleaved across + * the nodes and avoids having to allocate multiple + * hash-tables. + * + * NOTE: this isn't perfectly uniform, but it is fast and + * handles sparse node masks. + */ + node = (hash >> futex_hashshift) % nr_node_ids; + if (!node_possible(node)) { + node = find_next_bit_wrap(node_possible_map.bits, + nr_node_ids, node); + } + } + + return &futex_queues[node][hash & futex_hashmask]; +} /** * futex_setup_timer - set up the sleeping hrtimer. @@ -227,25 +552,60 @@ int get_futex_key(u32 __user *uaddr, unsigned int flags, union futex_key *key, struct page *page; struct folio *folio; struct address_space *mapping; - int err, ro = 0; + int node, err, size, ro = 0; + bool node_updated = false; bool fshared; fshared = flags & FLAGS_SHARED; + size = futex_size(flags); + if (flags & FLAGS_NUMA) + size *= 2; /* * The futex address must be "naturally" aligned. */ key->both.offset = address % PAGE_SIZE; - if (unlikely((address % sizeof(u32)) != 0)) + if (unlikely((address % size) != 0)) return -EINVAL; address -= key->both.offset; - if (unlikely(!access_ok(uaddr, sizeof(u32)))) + if (unlikely(!access_ok(uaddr, size))) return -EFAULT; if (unlikely(should_fail_futex(fshared))) return -EFAULT; + node = FUTEX_NO_NODE; + + if (flags & FLAGS_NUMA) { + u32 __user *naddr = (void *)uaddr + size / 2; + + if (futex_get_value(&node, naddr)) + return -EFAULT; + + if (node != FUTEX_NO_NODE && + (node >= MAX_NUMNODES || !node_possible(node))) + return -EINVAL; + } + + if (node == FUTEX_NO_NODE && (flags & FLAGS_MPOL)) { + node = futex_mpol(mm, address); + node_updated = true; + } + + if (flags & FLAGS_NUMA) { + u32 __user *naddr = (void *)uaddr + size / 2; + + if (node == FUTEX_NO_NODE) { + node = numa_node_id(); + node_updated = true; + } + if (node_updated && futex_put_value(node, naddr)) + return -EFAULT; + } + + key->both.node = node; + /* * PROCESS_PRIVATE futexes are fast. * As the mm cannot disappear under us and the 'key' only needs @@ -502,13 +862,9 @@ void __futex_unqueue(struct futex_q *q) } /* The key must be already stored in q->key. */ -struct futex_hash_bucket *futex_q_lock(struct futex_q *q) +void futex_q_lock(struct futex_q *q, struct futex_hash_bucket *hb) __acquires(&hb->lock) { - struct futex_hash_bucket *hb; - - hb = futex_hash(&q->key); - /* * Increment the counter before taking the lock so that * a potential waker won't miss a to-be-slept task that is @@ -522,14 +878,13 @@ struct futex_hash_bucket *futex_q_lock(struct futex_q *q) q->lock_ptr = &hb->lock; spin_lock(&hb->lock); - return hb; } void futex_q_unlock(struct futex_hash_bucket *hb) __releases(&hb->lock) { - spin_unlock(&hb->lock); futex_hb_waiters_dec(hb); + spin_unlock(&hb->lock); } void __futex_queue(struct futex_q *q, struct futex_hash_bucket *hb, @@ -568,6 +923,8 @@ int futex_unqueue(struct futex_q *q) spinlock_t *lock_ptr; int ret = 0; + /* RCU so lock_ptr is not going away during locking. */ + guard(rcu)(); /* In the common case we don't take the spinlock, which is nice. */ retry: /* @@ -606,6 +963,24 @@ retry: return ret; } +void futex_q_lockptr_lock(struct futex_q *q) +{ + spinlock_t *lock_ptr; + + /* + * See futex_unqueue() why lock_ptr can change. + */ + guard(rcu)(); +retry: + lock_ptr = READ_ONCE(q->lock_ptr); + spin_lock(lock_ptr); + + if (unlikely(lock_ptr != q->lock_ptr)) { + spin_unlock(lock_ptr); + goto retry; + } +} + /* * PI futexes can not be requeued and must remove themselves from the hash * bucket. The hash bucket lock (i.e. lock_ptr) is held. @@ -949,10 +1324,20 @@ static void exit_pi_state_list(struct task_struct *curr) { struct list_head *next, *head = &curr->pi_state_list; struct futex_pi_state *pi_state; - struct futex_hash_bucket *hb; union futex_key key = FUTEX_KEY_INIT; /* + * The mutex mm_struct::futex_hash_lock might be acquired. + */ + might_sleep(); + /* + * Ensure the hash remains stable (no resize) during the while loop + * below. The hb pointer is acquired under the pi_lock so we can't block + * on the mutex. + */ + WARN_ON(curr != current); + guard(private_hash)(); + /* * We are a ZOMBIE and nobody can enqueue itself on * pi_state_list anymore, but we have to be careful * versus waiters unqueueing themselves: @@ -962,50 +1347,52 @@ static void exit_pi_state_list(struct task_struct *curr) next = head->next; pi_state = list_entry(next, struct futex_pi_state, list); key = pi_state->key; - hb = futex_hash(&key); - - /* - * We can race against put_pi_state() removing itself from the - * list (a waiter going away). put_pi_state() will first - * decrement the reference count and then modify the list, so - * its possible to see the list entry but fail this reference - * acquire. - * - * In that case; drop the locks to let put_pi_state() make - * progress and retry the loop. - */ - if (!refcount_inc_not_zero(&pi_state->refcount)) { + if (1) { + CLASS(hb, hb)(&key); + + /* + * We can race against put_pi_state() removing itself from the + * list (a waiter going away). put_pi_state() will first + * decrement the reference count and then modify the list, so + * its possible to see the list entry but fail this reference + * acquire. + * + * In that case; drop the locks to let put_pi_state() make + * progress and retry the loop. + */ + if (!refcount_inc_not_zero(&pi_state->refcount)) { + raw_spin_unlock_irq(&curr->pi_lock); + cpu_relax(); + raw_spin_lock_irq(&curr->pi_lock); + continue; + } raw_spin_unlock_irq(&curr->pi_lock); - cpu_relax(); - raw_spin_lock_irq(&curr->pi_lock); - continue; - } - raw_spin_unlock_irq(&curr->pi_lock); - spin_lock(&hb->lock); - raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock); - raw_spin_lock(&curr->pi_lock); - /* - * We dropped the pi-lock, so re-check whether this - * task still owns the PI-state: - */ - if (head->next != next) { - /* retain curr->pi_lock for the loop invariant */ - raw_spin_unlock(&pi_state->pi_mutex.wait_lock); + spin_lock(&hb->lock); + raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock); + raw_spin_lock(&curr->pi_lock); + /* + * We dropped the pi-lock, so re-check whether this + * task still owns the PI-state: + */ + if (head->next != next) { + /* retain curr->pi_lock for the loop invariant */ + raw_spin_unlock(&pi_state->pi_mutex.wait_lock); + spin_unlock(&hb->lock); + put_pi_state(pi_state); + continue; + } + + WARN_ON(pi_state->owner != curr); + WARN_ON(list_empty(&pi_state->list)); + list_del_init(&pi_state->list); + pi_state->owner = NULL; + + raw_spin_unlock(&curr->pi_lock); + raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock); spin_unlock(&hb->lock); - put_pi_state(pi_state); - continue; } - WARN_ON(pi_state->owner != curr); - WARN_ON(list_empty(&pi_state->list)); - list_del_init(&pi_state->list); - pi_state->owner = NULL; - - raw_spin_unlock(&curr->pi_lock); - raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock); - spin_unlock(&hb->lock); - rt_mutex_futex_unlock(&pi_state->pi_mutex); put_pi_state(pi_state); @@ -1125,30 +1512,304 @@ void futex_exit_release(struct task_struct *tsk) futex_cleanup_end(tsk, FUTEX_STATE_DEAD); } +static void futex_hash_bucket_init(struct futex_hash_bucket *fhb, + struct futex_private_hash *fph) +{ +#ifdef CONFIG_FUTEX_PRIVATE_HASH + fhb->priv = fph; +#endif + atomic_set(&fhb->waiters, 0); + plist_head_init(&fhb->chain); + spin_lock_init(&fhb->lock); +} + +#define FH_CUSTOM 0x01 +#define FH_IMMUTABLE 0x02 + +#ifdef CONFIG_FUTEX_PRIVATE_HASH +void futex_hash_free(struct mm_struct *mm) +{ + struct futex_private_hash *fph; + + kvfree(mm->futex_phash_new); + fph = rcu_dereference_raw(mm->futex_phash); + if (fph) { + WARN_ON_ONCE(rcuref_read(&fph->users) > 1); + kvfree(fph); + } +} + +static bool futex_pivot_pending(struct mm_struct *mm) +{ + struct futex_private_hash *fph; + + guard(rcu)(); + + if (!mm->futex_phash_new) + return true; + + fph = rcu_dereference(mm->futex_phash); + return rcuref_is_dead(&fph->users); +} + +static bool futex_hash_less(struct futex_private_hash *a, + struct futex_private_hash *b) +{ + /* user provided always wins */ + if (!a->custom && b->custom) + return true; + if (a->custom && !b->custom) + return false; + + /* zero-sized hash wins */ + if (!b->hash_mask) + return true; + if (!a->hash_mask) + return false; + + /* keep the biggest */ + if (a->hash_mask < b->hash_mask) + return true; + if (a->hash_mask > b->hash_mask) + return false; + + return false; /* equal */ +} + +static int futex_hash_allocate(unsigned int hash_slots, unsigned int flags) +{ + struct mm_struct *mm = current->mm; + struct futex_private_hash *fph; + bool custom = flags & FH_CUSTOM; + int i; + + if (hash_slots && (hash_slots == 1 || !is_power_of_2(hash_slots))) + return -EINVAL; + + /* + * Once we've disabled the global hash there is no way back. + */ + scoped_guard(rcu) { + fph = rcu_dereference(mm->futex_phash); + if (fph && (!fph->hash_mask || fph->immutable)) { + if (custom) + return -EBUSY; + return 0; + } + } + + fph = kvzalloc(struct_size(fph, queues, hash_slots), GFP_KERNEL_ACCOUNT | __GFP_NOWARN); + if (!fph) + return -ENOMEM; + + rcuref_init(&fph->users, 1); + fph->hash_mask = hash_slots ? hash_slots - 1 : 0; + fph->custom = custom; + fph->immutable = !!(flags & FH_IMMUTABLE); + fph->mm = mm; + + for (i = 0; i < hash_slots; i++) + futex_hash_bucket_init(&fph->queues[i], fph); + + if (custom) { + /* + * Only let prctl() wait / retry; don't unduly delay clone(). + */ +again: + wait_var_event(mm, futex_pivot_pending(mm)); + } + + scoped_guard(mutex, &mm->futex_hash_lock) { + struct futex_private_hash *free __free(kvfree) = NULL; + struct futex_private_hash *cur, *new; + + cur = rcu_dereference_protected(mm->futex_phash, + lockdep_is_held(&mm->futex_hash_lock)); + new = mm->futex_phash_new; + mm->futex_phash_new = NULL; + + if (fph) { + if (cur && !new) { + /* + * If we have an existing hash, but do not yet have + * allocated a replacement hash, drop the initial + * reference on the existing hash. + */ + futex_private_hash_put(cur); + } + + if (new) { + /* + * Two updates raced; throw out the lesser one. + */ + if (futex_hash_less(new, fph)) { + free = new; + new = fph; + } else { + free = fph; + } + } else { + new = fph; + } + fph = NULL; + } + + if (new) { + /* + * Will set mm->futex_phash_new on failure; + * futex_private_hash_get() will try again. + */ + if (!__futex_pivot_hash(mm, new) && custom) + goto again; + } + } + return 0; +} + +int futex_hash_allocate_default(void) +{ + unsigned int threads, buckets, current_buckets = 0; + struct futex_private_hash *fph; + + if (!current->mm) + return 0; + + scoped_guard(rcu) { + threads = min_t(unsigned int, + get_nr_threads(current), + num_online_cpus()); + + fph = rcu_dereference(current->mm->futex_phash); + if (fph) { + if (fph->custom) + return 0; + + current_buckets = fph->hash_mask + 1; + } + } + + /* + * The default allocation will remain within + * 16 <= threads * 4 <= global hash size + */ + buckets = roundup_pow_of_two(4 * threads); + buckets = clamp(buckets, 16, futex_hashmask + 1); + + if (current_buckets >= buckets) + return 0; + + return futex_hash_allocate(buckets, 0); +} + +static int futex_hash_get_slots(void) +{ + struct futex_private_hash *fph; + + guard(rcu)(); + fph = rcu_dereference(current->mm->futex_phash); + if (fph && fph->hash_mask) + return fph->hash_mask + 1; + return 0; +} + +static int futex_hash_get_immutable(void) +{ + struct futex_private_hash *fph; + + guard(rcu)(); + fph = rcu_dereference(current->mm->futex_phash); + if (fph && fph->immutable) + return 1; + if (fph && !fph->hash_mask) + return 1; + return 0; +} + +#else + +static int futex_hash_allocate(unsigned int hash_slots, unsigned int flags) +{ + return -EINVAL; +} + +static int futex_hash_get_slots(void) +{ + return 0; +} + +static int futex_hash_get_immutable(void) +{ + return 0; +} +#endif + +int futex_hash_prctl(unsigned long arg2, unsigned long arg3, unsigned long arg4) +{ + unsigned int flags = FH_CUSTOM; + int ret; + + switch (arg2) { + case PR_FUTEX_HASH_SET_SLOTS: + if (arg4 & ~FH_FLAG_IMMUTABLE) + return -EINVAL; + if (arg4 & FH_FLAG_IMMUTABLE) + flags |= FH_IMMUTABLE; + ret = futex_hash_allocate(arg3, flags); + break; + + case PR_FUTEX_HASH_GET_SLOTS: + ret = futex_hash_get_slots(); + break; + + case PR_FUTEX_HASH_GET_IMMUTABLE: + ret = futex_hash_get_immutable(); + break; + + default: + ret = -EINVAL; + break; + } + return ret; +} + static int __init futex_init(void) { unsigned long hashsize, i; - unsigned int futex_shift; + unsigned int order, n; + unsigned long size; #ifdef CONFIG_BASE_SMALL hashsize = 16; #else - hashsize = roundup_pow_of_two(256 * num_possible_cpus()); + hashsize = 256 * num_possible_cpus(); + hashsize /= num_possible_nodes(); + hashsize = max(4, hashsize); + hashsize = roundup_pow_of_two(hashsize); #endif + futex_hashshift = ilog2(hashsize); + size = sizeof(struct futex_hash_bucket) * hashsize; + order = get_order(size); + + for_each_node(n) { + struct futex_hash_bucket *table; + + if (order > MAX_PAGE_ORDER) + table = vmalloc_huge_node(size, GFP_KERNEL, n); + else + table = alloc_pages_exact_nid(n, size, GFP_KERNEL); + + BUG_ON(!table); - futex_queues = alloc_large_system_hash("futex", sizeof(*futex_queues), - hashsize, 0, 0, - &futex_shift, NULL, - hashsize, hashsize); - hashsize = 1UL << futex_shift; + for (i = 0; i < hashsize; i++) + futex_hash_bucket_init(&table[i], NULL); - for (i = 0; i < hashsize; i++) { - atomic_set(&futex_queues[i].waiters, 0); - plist_head_init(&futex_queues[i].chain); - spin_lock_init(&futex_queues[i].lock); + futex_queues[n] = table; } futex_hashmask = hashsize - 1; + pr_info("futex hash table entries: %lu (%lu bytes on %d NUMA nodes, total %lu KiB, %s).\n", + hashsize, size, num_possible_nodes(), size * num_possible_nodes() / 1024, + order > MAX_PAGE_ORDER ? "vmalloc" : "linear"); return 0; } core_initcall(futex_init); diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index 6b2f4c7eb720fd..fcd1617212eed0 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -7,6 +7,7 @@ #include <linux/sched/wake_q.h> #include <linux/compat.h> #include <linux/uaccess.h> +#include <linux/cleanup.h> #ifdef CONFIG_PREEMPT_RT #include <linux/rcuwait.h> @@ -38,6 +39,7 @@ #define FLAGS_HAS_TIMEOUT 0x0040 #define FLAGS_NUMA 0x0080 #define FLAGS_STRICT 0x0100 +#define FLAGS_MPOL 0x0200 /* FUTEX_ to FLAGS_ */ static inline unsigned int futex_to_flags(unsigned int op) @@ -53,7 +55,7 @@ static inline unsigned int futex_to_flags(unsigned int op) return flags; } -#define FUTEX2_VALID_MASK (FUTEX2_SIZE_MASK | FUTEX2_PRIVATE) +#define FUTEX2_VALID_MASK (FUTEX2_SIZE_MASK | FUTEX2_NUMA | FUTEX2_MPOL | FUTEX2_PRIVATE) /* FUTEX2_ to FLAGS_ */ static inline unsigned int futex2_to_flags(unsigned int flags2) @@ -66,6 +68,9 @@ static inline unsigned int futex2_to_flags(unsigned int flags2) if (flags2 & FUTEX2_NUMA) flags |= FLAGS_NUMA; + if (flags2 & FUTEX2_MPOL) + flags |= FLAGS_MPOL; + return flags; } @@ -86,6 +91,19 @@ static inline bool futex_flags_valid(unsigned int flags) if ((flags & FLAGS_SIZE_MASK) != FLAGS_SIZE_32) return false; + /* + * Must be able to represent both FUTEX_NO_NODE and every valid nodeid + * in a futex word. + */ + if (flags & FLAGS_NUMA) { + int bits = 8 * futex_size(flags); + u64 max = ~0ULL; + + max >>= 64 - bits; + if (nr_node_ids >= max) + return false; + } + return true; } @@ -117,6 +135,7 @@ struct futex_hash_bucket { atomic_t waiters; spinlock_t lock; struct plist_head chain; + struct futex_private_hash *priv; } ____cacheline_aligned_in_smp; /* @@ -156,6 +175,7 @@ typedef void (futex_wake_fn)(struct wake_q_head *wake_q, struct futex_q *q); * @requeue_pi_key: the requeue_pi target futex key * @bitset: bitset for the optional bitmasked wakeup * @requeue_state: State field for futex_requeue_pi() + * @drop_hb_ref: Waiter should drop the extra hash bucket reference if true * @requeue_wait: RCU wait for futex_requeue_pi() (RT only) * * We use this hashed waitqueue, instead of a normal wait_queue_entry_t, so @@ -182,6 +202,7 @@ struct futex_q { union futex_key *requeue_pi_key; u32 bitset; atomic_t requeue_state; + bool drop_hb_ref; #ifdef CONFIG_PREEMPT_RT struct rcuwait requeue_wait; #endif @@ -196,12 +217,35 @@ enum futex_access { extern int get_futex_key(u32 __user *uaddr, unsigned int flags, union futex_key *key, enum futex_access rw); - +extern void futex_q_lockptr_lock(struct futex_q *q); extern struct hrtimer_sleeper * futex_setup_timer(ktime_t *time, struct hrtimer_sleeper *timeout, int flags, u64 range_ns); extern struct futex_hash_bucket *futex_hash(union futex_key *key); +#ifdef CONFIG_FUTEX_PRIVATE_HASH +extern void futex_hash_get(struct futex_hash_bucket *hb); +extern void futex_hash_put(struct futex_hash_bucket *hb); + +extern struct futex_private_hash *futex_private_hash(void); +extern bool futex_private_hash_get(struct futex_private_hash *fph); +extern void futex_private_hash_put(struct futex_private_hash *fph); + +#else /* !CONFIG_FUTEX_PRIVATE_HASH */ +static inline void futex_hash_get(struct futex_hash_bucket *hb) { } +static inline void futex_hash_put(struct futex_hash_bucket *hb) { } +static inline struct futex_private_hash *futex_private_hash(void) { return NULL; } +static inline bool futex_private_hash_get(void) { return false; } +static inline void futex_private_hash_put(struct futex_private_hash *fph) { } +#endif + +DEFINE_CLASS(hb, struct futex_hash_bucket *, + if (_T) futex_hash_put(_T), + futex_hash(key), union futex_key *key); + +DEFINE_CLASS(private_hash, struct futex_private_hash *, + if (_T) futex_private_hash_put(_T), + futex_private_hash(), void); /** * futex_match - Check whether two futex keys are equal @@ -219,9 +263,9 @@ static inline int futex_match(union futex_key *key1, union futex_key *key2) } extern int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags, - struct futex_q *q, struct futex_hash_bucket **hb); -extern void futex_wait_queue(struct futex_hash_bucket *hb, struct futex_q *q, - struct hrtimer_sleeper *timeout); + struct futex_q *q, union futex_key *key2, + struct task_struct *task); +extern void futex_do_wait(struct futex_q *q, struct hrtimer_sleeper *timeout); extern bool __futex_wake_mark(struct futex_q *q); extern void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q); @@ -256,7 +300,7 @@ static inline int futex_cmpxchg_value_locked(u32 *curval, u32 __user *uaddr, u32 * This looks a bit overkill, but generally just results in a couple * of instructions. */ -static __always_inline int futex_read_inatomic(u32 *dest, u32 __user *from) +static __always_inline int futex_get_value(u32 *dest, u32 __user *from) { u32 val; @@ -273,12 +317,26 @@ Efault: return -EFAULT; } +static __always_inline int futex_put_value(u32 val, u32 __user *to) +{ + if (can_do_masked_user_access()) + to = masked_user_access_begin(to); + else if (!user_read_access_begin(to, sizeof(*to))) + return -EFAULT; + unsafe_put_user(val, to, Efault); + user_read_access_end(); + return 0; +Efault: + user_read_access_end(); + return -EFAULT; +} + static inline int futex_get_value_locked(u32 *dest, u32 __user *from) { int ret; pagefault_disable(); - ret = futex_read_inatomic(dest, from); + ret = futex_get_value(dest, from); pagefault_enable(); return ret; @@ -354,7 +412,7 @@ static inline int futex_hb_waiters_pending(struct futex_hash_bucket *hb) #endif } -extern struct futex_hash_bucket *futex_q_lock(struct futex_q *q); +extern void futex_q_lock(struct futex_q *q, struct futex_hash_bucket *hb); extern void futex_q_unlock(struct futex_hash_bucket *hb); diff --git a/kernel/futex/pi.c b/kernel/futex/pi.c index 7a941845f7eeeb..dacb2330f1fbcc 100644 --- a/kernel/futex/pi.c +++ b/kernel/futex/pi.c @@ -806,7 +806,7 @@ handle_err: break; } - spin_lock(q->lock_ptr); + futex_q_lockptr_lock(q); raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock); /* @@ -920,7 +920,6 @@ int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int tryl struct hrtimer_sleeper timeout, *to; struct task_struct *exiting = NULL; struct rt_mutex_waiter rt_waiter; - struct futex_hash_bucket *hb; struct futex_q q = futex_q_init; DEFINE_WAKE_Q(wake_q); int res, ret; @@ -939,151 +938,183 @@ retry: goto out; retry_private: - hb = futex_q_lock(&q); + if (1) { + CLASS(hb, hb)(&q.key); - ret = futex_lock_pi_atomic(uaddr, hb, &q.key, &q.pi_state, current, - &exiting, 0); - if (unlikely(ret)) { - /* - * Atomic work succeeded and we got the lock, - * or failed. Either way, we do _not_ block. - */ - switch (ret) { - case 1: - /* We got the lock. */ - ret = 0; - goto out_unlock_put_key; - case -EFAULT: - goto uaddr_faulted; - case -EBUSY: - case -EAGAIN: - /* - * Two reasons for this: - * - EBUSY: Task is exiting and we just wait for the - * exit to complete. - * - EAGAIN: The user space value changed. - */ - futex_q_unlock(hb); + futex_q_lock(&q, hb); + + ret = futex_lock_pi_atomic(uaddr, hb, &q.key, &q.pi_state, current, + &exiting, 0); + if (unlikely(ret)) { /* - * Handle the case where the owner is in the middle of - * exiting. Wait for the exit to complete otherwise - * this task might loop forever, aka. live lock. + * Atomic work succeeded and we got the lock, + * or failed. Either way, we do _not_ block. */ - wait_for_owner_exiting(ret, exiting); - cond_resched(); - goto retry; - default: - goto out_unlock_put_key; + switch (ret) { + case 1: + /* We got the lock. */ + ret = 0; + goto out_unlock_put_key; + case -EFAULT: + goto uaddr_faulted; + case -EBUSY: + case -EAGAIN: + /* + * Two reasons for this: + * - EBUSY: Task is exiting and we just wait for the + * exit to complete. + * - EAGAIN: The user space value changed. + */ + futex_q_unlock(hb); + /* + * Handle the case where the owner is in the middle of + * exiting. Wait for the exit to complete otherwise + * this task might loop forever, aka. live lock. + */ + wait_for_owner_exiting(ret, exiting); + cond_resched(); + goto retry; + default: + goto out_unlock_put_key; + } } - } - WARN_ON(!q.pi_state); + WARN_ON(!q.pi_state); - /* - * Only actually queue now that the atomic ops are done: - */ - __futex_queue(&q, hb, current); + /* + * Only actually queue now that the atomic ops are done: + */ + __futex_queue(&q, hb, current); - if (trylock) { - ret = rt_mutex_futex_trylock(&q.pi_state->pi_mutex); - /* Fixup the trylock return value: */ - ret = ret ? 0 : -EWOULDBLOCK; - goto no_block; - } + if (trylock) { + ret = rt_mutex_futex_trylock(&q.pi_state->pi_mutex); + /* Fixup the trylock return value: */ + ret = ret ? 0 : -EWOULDBLOCK; + goto no_block; + } - /* - * Must be done before we enqueue the waiter, here is unfortunately - * under the hb lock, but that *should* work because it does nothing. - */ - rt_mutex_pre_schedule(); + /* + * Caution; releasing @hb in-scope. The hb->lock is still locked + * while the reference is dropped. The reference can not be dropped + * after the unlock because if a user initiated resize is in progress + * then we might need to wake him. This can not be done after the + * rt_mutex_pre_schedule() invocation. The hb will remain valid because + * the thread, performing resize, will block on hb->lock during + * the requeue. + */ + futex_hash_put(no_free_ptr(hb)); + /* + * Must be done before we enqueue the waiter, here is unfortunately + * under the hb lock, but that *should* work because it does nothing. + */ + rt_mutex_pre_schedule(); - rt_mutex_init_waiter(&rt_waiter); + rt_mutex_init_waiter(&rt_waiter); - /* - * On PREEMPT_RT, when hb->lock becomes an rt_mutex, we must not - * hold it while doing rt_mutex_start_proxy(), because then it will - * include hb->lock in the blocking chain, even through we'll not in - * fact hold it while blocking. This will lead it to report -EDEADLK - * and BUG when futex_unlock_pi() interleaves with this. - * - * Therefore acquire wait_lock while holding hb->lock, but drop the - * latter before calling __rt_mutex_start_proxy_lock(). This - * interleaves with futex_unlock_pi() -- which does a similar lock - * handoff -- such that the latter can observe the futex_q::pi_state - * before __rt_mutex_start_proxy_lock() is done. - */ - raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock); - spin_unlock(q.lock_ptr); - /* - * __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter - * such that futex_unlock_pi() is guaranteed to observe the waiter when - * it sees the futex_q::pi_state. - */ - ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current, &wake_q); - raw_spin_unlock_irq_wake(&q.pi_state->pi_mutex.wait_lock, &wake_q); + /* + * On PREEMPT_RT, when hb->lock becomes an rt_mutex, we must not + * hold it while doing rt_mutex_start_proxy(), because then it will + * include hb->lock in the blocking chain, even through we'll not in + * fact hold it while blocking. This will lead it to report -EDEADLK + * and BUG when futex_unlock_pi() interleaves with this. + * + * Therefore acquire wait_lock while holding hb->lock, but drop the + * latter before calling __rt_mutex_start_proxy_lock(). This + * interleaves with futex_unlock_pi() -- which does a similar lock + * handoff -- such that the latter can observe the futex_q::pi_state + * before __rt_mutex_start_proxy_lock() is done. + */ + raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock); + spin_unlock(q.lock_ptr); + /* + * __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter + * such that futex_unlock_pi() is guaranteed to observe the waiter when + * it sees the futex_q::pi_state. + */ + ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current, &wake_q); + raw_spin_unlock_irq_wake(&q.pi_state->pi_mutex.wait_lock, &wake_q); - if (ret) { - if (ret == 1) - ret = 0; - goto cleanup; - } + if (ret) { + if (ret == 1) + ret = 0; + goto cleanup; + } - if (unlikely(to)) - hrtimer_sleeper_start_expires(to, HRTIMER_MODE_ABS); + if (unlikely(to)) + hrtimer_sleeper_start_expires(to, HRTIMER_MODE_ABS); - ret = rt_mutex_wait_proxy_lock(&q.pi_state->pi_mutex, to, &rt_waiter); + ret = rt_mutex_wait_proxy_lock(&q.pi_state->pi_mutex, to, &rt_waiter); cleanup: - /* - * If we failed to acquire the lock (deadlock/signal/timeout), we must - * must unwind the above, however we canont lock hb->lock because - * rt_mutex already has a waiter enqueued and hb->lock can itself try - * and enqueue an rt_waiter through rtlock. - * - * Doing the cleanup without holding hb->lock can cause inconsistent - * state between hb and pi_state, but only in the direction of not - * seeing a waiter that is leaving. - * - * See futex_unlock_pi(), it deals with this inconsistency. - * - * There be dragons here, since we must deal with the inconsistency on - * the way out (here), it is impossible to detect/warn about the race - * the other way around (missing an incoming waiter). - * - * What could possibly go wrong... - */ - if (ret && !rt_mutex_cleanup_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter)) - ret = 0; + /* + * If we failed to acquire the lock (deadlock/signal/timeout), we must + * unwind the above, however we canont lock hb->lock because + * rt_mutex already has a waiter enqueued and hb->lock can itself try + * and enqueue an rt_waiter through rtlock. + * + * Doing the cleanup without holding hb->lock can cause inconsistent + * state between hb and pi_state, but only in the direction of not + * seeing a waiter that is leaving. + * + * See futex_unlock_pi(), it deals with this inconsistency. + * + * There be dragons here, since we must deal with the inconsistency on + * the way out (here), it is impossible to detect/warn about the race + * the other way around (missing an incoming waiter). + * + * What could possibly go wrong... + */ + if (ret && !rt_mutex_cleanup_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter)) + ret = 0; - /* - * Now that the rt_waiter has been dequeued, it is safe to use - * spinlock/rtlock (which might enqueue its own rt_waiter) and fix up - * the - */ - spin_lock(q.lock_ptr); - /* - * Waiter is unqueued. - */ - rt_mutex_post_schedule(); + /* + * Now that the rt_waiter has been dequeued, it is safe to use + * spinlock/rtlock (which might enqueue its own rt_waiter) and fix up + * the + */ + futex_q_lockptr_lock(&q); + /* + * Waiter is unqueued. + */ + rt_mutex_post_schedule(); no_block: - /* - * Fixup the pi_state owner and possibly acquire the lock if we - * haven't already. - */ - res = fixup_pi_owner(uaddr, &q, !ret); - /* - * If fixup_pi_owner() returned an error, propagate that. If it acquired - * the lock, clear our -ETIMEDOUT or -EINTR. - */ - if (res) - ret = (res < 0) ? res : 0; - - futex_unqueue_pi(&q); - spin_unlock(q.lock_ptr); - goto out; + /* + * Fixup the pi_state owner and possibly acquire the lock if we + * haven't already. + */ + res = fixup_pi_owner(uaddr, &q, !ret); + /* + * If fixup_pi_owner() returned an error, propagate that. If it acquired + * the lock, clear our -ETIMEDOUT or -EINTR. + */ + if (res) + ret = (res < 0) ? res : 0; + + futex_unqueue_pi(&q); + spin_unlock(q.lock_ptr); + if (q.drop_hb_ref) { + CLASS(hb, hb)(&q.key); + /* Additional reference from futex_unlock_pi() */ + futex_hash_put(hb); + } + goto out; out_unlock_put_key: - futex_q_unlock(hb); + futex_q_unlock(hb); + goto out; + +uaddr_faulted: + futex_q_unlock(hb); + + ret = fault_in_user_writeable(uaddr); + if (ret) + goto out; + + if (!(flags & FLAGS_SHARED)) + goto retry_private; + + goto retry; + } out: if (to) { @@ -1091,18 +1122,6 @@ out: destroy_hrtimer_on_stack(&to->timer); } return ret != -EINTR ? ret : -ERESTARTNOINTR; - -uaddr_faulted: - futex_q_unlock(hb); - - ret = fault_in_user_writeable(uaddr); - if (ret) - goto out; - - if (!(flags & FLAGS_SHARED)) - goto retry_private; - - goto retry; } /* @@ -1114,7 +1133,6 @@ int futex_unlock_pi(u32 __user *uaddr, unsigned int flags) { u32 curval, uval, vpid = task_pid_vnr(current); union futex_key key = FUTEX_KEY_INIT; - struct futex_hash_bucket *hb; struct futex_q *top_waiter; int ret; @@ -1134,7 +1152,7 @@ retry: if (ret) return ret; - hb = futex_hash(&key); + CLASS(hb, hb)(&key); spin_lock(&hb->lock); retry_hb: @@ -1187,6 +1205,12 @@ retry_hb: */ rt_waiter = rt_mutex_top_waiter(&pi_state->pi_mutex); if (!rt_waiter) { + /* + * Acquire a reference for the leaving waiter to ensure + * valid futex_q::lock_ptr. + */ + futex_hash_get(hb); + top_waiter->drop_hb_ref = true; __futex_unqueue(top_waiter); raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock); goto retry_hb; diff --git a/kernel/futex/requeue.c b/kernel/futex/requeue.c index b47bb764b35201..c716a66f86929c 100644 --- a/kernel/futex/requeue.c +++ b/kernel/futex/requeue.c @@ -87,6 +87,11 @@ void requeue_futex(struct futex_q *q, struct futex_hash_bucket *hb1, futex_hb_waiters_inc(hb2); plist_add(&q->list, &hb2->chain); q->lock_ptr = &hb2->lock; + /* + * hb1 and hb2 belong to the same futex_hash_bucket_private + * because if we managed get a reference on hb1 then it can't be + * replaced. Therefore we avoid put(hb1)+get(hb2) here. + */ } q->key = *key2; } @@ -231,7 +236,12 @@ void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key, WARN_ON(!q->rt_waiter); q->rt_waiter = NULL; - + /* + * Acquire a reference for the waiter to ensure valid + * futex_q::lock_ptr. + */ + futex_hash_get(hb); + q->drop_hb_ref = true; q->lock_ptr = &hb->lock; /* Signal locked state to the waiter */ @@ -371,7 +381,6 @@ int futex_requeue(u32 __user *uaddr1, unsigned int flags1, union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT; int task_count = 0, ret; struct futex_pi_state *pi_state = NULL; - struct futex_hash_bucket *hb1, *hb2; struct futex_q *this, *next; DEFINE_WAKE_Q(wake_q); @@ -443,240 +452,242 @@ retry: if (requeue_pi && futex_match(&key1, &key2)) return -EINVAL; - hb1 = futex_hash(&key1); - hb2 = futex_hash(&key2); - retry_private: - futex_hb_waiters_inc(hb2); - double_lock_hb(hb1, hb2); + if (1) { + CLASS(hb, hb1)(&key1); + CLASS(hb, hb2)(&key2); - if (likely(cmpval != NULL)) { - u32 curval; + futex_hb_waiters_inc(hb2); + double_lock_hb(hb1, hb2); - ret = futex_get_value_locked(&curval, uaddr1); + if (likely(cmpval != NULL)) { + u32 curval; - if (unlikely(ret)) { - double_unlock_hb(hb1, hb2); - futex_hb_waiters_dec(hb2); + ret = futex_get_value_locked(&curval, uaddr1); - ret = get_user(curval, uaddr1); - if (ret) - return ret; + if (unlikely(ret)) { + futex_hb_waiters_dec(hb2); + double_unlock_hb(hb1, hb2); - if (!(flags1 & FLAGS_SHARED)) - goto retry_private; + ret = get_user(curval, uaddr1); + if (ret) + return ret; - goto retry; - } - if (curval != *cmpval) { - ret = -EAGAIN; - goto out_unlock; - } - } + if (!(flags1 & FLAGS_SHARED)) + goto retry_private; - if (requeue_pi) { - struct task_struct *exiting = NULL; + goto retry; + } + if (curval != *cmpval) { + ret = -EAGAIN; + goto out_unlock; + } + } - /* - * Attempt to acquire uaddr2 and wake the top waiter. If we - * intend to requeue waiters, force setting the FUTEX_WAITERS - * bit. We force this here where we are able to easily handle - * faults rather in the requeue loop below. - * - * Updates topwaiter::requeue_state if a top waiter exists. - */ - ret = futex_proxy_trylock_atomic(uaddr2, hb1, hb2, &key1, - &key2, &pi_state, - &exiting, nr_requeue); + if (requeue_pi) { + struct task_struct *exiting = NULL; - /* - * At this point the top_waiter has either taken uaddr2 or - * is waiting on it. In both cases pi_state has been - * established and an initial refcount on it. In case of an - * error there's nothing. - * - * The top waiter's requeue_state is up to date: - * - * - If the lock was acquired atomically (ret == 1), then - * the state is Q_REQUEUE_PI_LOCKED. - * - * The top waiter has been dequeued and woken up and can - * return to user space immediately. The kernel/user - * space state is consistent. In case that there must be - * more waiters requeued the WAITERS bit in the user - * space futex is set so the top waiter task has to go - * into the syscall slowpath to unlock the futex. This - * will block until this requeue operation has been - * completed and the hash bucket locks have been - * dropped. - * - * - If the trylock failed with an error (ret < 0) then - * the state is either Q_REQUEUE_PI_NONE, i.e. "nothing - * happened", or Q_REQUEUE_PI_IGNORE when there was an - * interleaved early wakeup. - * - * - If the trylock did not succeed (ret == 0) then the - * state is either Q_REQUEUE_PI_IN_PROGRESS or - * Q_REQUEUE_PI_WAIT if an early wakeup interleaved. - * This will be cleaned up in the loop below, which - * cannot fail because futex_proxy_trylock_atomic() did - * the same sanity checks for requeue_pi as the loop - * below does. - */ - switch (ret) { - case 0: - /* We hold a reference on the pi state. */ - break; - - case 1: /* - * futex_proxy_trylock_atomic() acquired the user space - * futex. Adjust task_count. + * Attempt to acquire uaddr2 and wake the top waiter. If we + * intend to requeue waiters, force setting the FUTEX_WAITERS + * bit. We force this here where we are able to easily handle + * faults rather in the requeue loop below. + * + * Updates topwaiter::requeue_state if a top waiter exists. */ - task_count++; - ret = 0; - break; + ret = futex_proxy_trylock_atomic(uaddr2, hb1, hb2, &key1, + &key2, &pi_state, + &exiting, nr_requeue); - /* - * If the above failed, then pi_state is NULL and - * waiter::requeue_state is correct. - */ - case -EFAULT: - double_unlock_hb(hb1, hb2); - futex_hb_waiters_dec(hb2); - ret = fault_in_user_writeable(uaddr2); - if (!ret) - goto retry; - return ret; - case -EBUSY: - case -EAGAIN: - /* - * Two reasons for this: - * - EBUSY: Owner is exiting and we just wait for the - * exit to complete. - * - EAGAIN: The user space value changed. - */ - double_unlock_hb(hb1, hb2); - futex_hb_waiters_dec(hb2); /* - * Handle the case where the owner is in the middle of - * exiting. Wait for the exit to complete otherwise - * this task might loop forever, aka. live lock. + * At this point the top_waiter has either taken uaddr2 or + * is waiting on it. In both cases pi_state has been + * established and an initial refcount on it. In case of an + * error there's nothing. + * + * The top waiter's requeue_state is up to date: + * + * - If the lock was acquired atomically (ret == 1), then + * the state is Q_REQUEUE_PI_LOCKED. + * + * The top waiter has been dequeued and woken up and can + * return to user space immediately. The kernel/user + * space state is consistent. In case that there must be + * more waiters requeued the WAITERS bit in the user + * space futex is set so the top waiter task has to go + * into the syscall slowpath to unlock the futex. This + * will block until this requeue operation has been + * completed and the hash bucket locks have been + * dropped. + * + * - If the trylock failed with an error (ret < 0) then + * the state is either Q_REQUEUE_PI_NONE, i.e. "nothing + * happened", or Q_REQUEUE_PI_IGNORE when there was an + * interleaved early wakeup. + * + * - If the trylock did not succeed (ret == 0) then the + * state is either Q_REQUEUE_PI_IN_PROGRESS or + * Q_REQUEUE_PI_WAIT if an early wakeup interleaved. + * This will be cleaned up in the loop below, which + * cannot fail because futex_proxy_trylock_atomic() did + * the same sanity checks for requeue_pi as the loop + * below does. */ - wait_for_owner_exiting(ret, exiting); - cond_resched(); - goto retry; - default: - goto out_unlock; - } - } - - plist_for_each_entry_safe(this, next, &hb1->chain, list) { - if (task_count - nr_wake >= nr_requeue) - break; - - if (!futex_match(&this->key, &key1)) - continue; - - /* - * FUTEX_WAIT_REQUEUE_PI and FUTEX_CMP_REQUEUE_PI should always - * be paired with each other and no other futex ops. - * - * We should never be requeueing a futex_q with a pi_state, - * which is awaiting a futex_unlock_pi(). - */ - if ((requeue_pi && !this->rt_waiter) || - (!requeue_pi && this->rt_waiter) || - this->pi_state) { - ret = -EINVAL; - break; + switch (ret) { + case 0: + /* We hold a reference on the pi state. */ + break; + + case 1: + /* + * futex_proxy_trylock_atomic() acquired the user space + * futex. Adjust task_count. + */ + task_count++; + ret = 0; + break; + + /* + * If the above failed, then pi_state is NULL and + * waiter::requeue_state is correct. + */ + case -EFAULT: + futex_hb_waiters_dec(hb2); + double_unlock_hb(hb1, hb2); + ret = fault_in_user_writeable(uaddr2); + if (!ret) + goto retry; + return ret; + case -EBUSY: + case -EAGAIN: + /* + * Two reasons for this: + * - EBUSY: Owner is exiting and we just wait for the + * exit to complete. + * - EAGAIN: The user space value changed. + */ + futex_hb_waiters_dec(hb2); + double_unlock_hb(hb1, hb2); + /* + * Handle the case where the owner is in the middle of + * exiting. Wait for the exit to complete otherwise + * this task might loop forever, aka. live lock. + */ + wait_for_owner_exiting(ret, exiting); + cond_resched(); + goto retry; + default: + goto out_unlock; + } } - /* Plain futexes just wake or requeue and are done */ - if (!requeue_pi) { - if (++task_count <= nr_wake) - this->wake(&wake_q, this); - else - requeue_futex(this, hb1, hb2, &key2); - continue; - } + plist_for_each_entry_safe(this, next, &hb1->chain, list) { + if (task_count - nr_wake >= nr_requeue) + break; - /* Ensure we requeue to the expected futex for requeue_pi. */ - if (!futex_match(this->requeue_pi_key, &key2)) { - ret = -EINVAL; - break; - } + if (!futex_match(&this->key, &key1)) + continue; - /* - * Requeue nr_requeue waiters and possibly one more in the case - * of requeue_pi if we couldn't acquire the lock atomically. - * - * Prepare the waiter to take the rt_mutex. Take a refcount - * on the pi_state and store the pointer in the futex_q - * object of the waiter. - */ - get_pi_state(pi_state); - - /* Don't requeue when the waiter is already on the way out. */ - if (!futex_requeue_pi_prepare(this, pi_state)) { /* - * Early woken waiter signaled that it is on the - * way out. Drop the pi_state reference and try the - * next waiter. @this->pi_state is still NULL. + * FUTEX_WAIT_REQUEUE_PI and FUTEX_CMP_REQUEUE_PI should always + * be paired with each other and no other futex ops. + * + * We should never be requeueing a futex_q with a pi_state, + * which is awaiting a futex_unlock_pi(). */ - put_pi_state(pi_state); - continue; - } + if ((requeue_pi && !this->rt_waiter) || + (!requeue_pi && this->rt_waiter) || + this->pi_state) { + ret = -EINVAL; + break; + } + + /* Plain futexes just wake or requeue and are done */ + if (!requeue_pi) { + if (++task_count <= nr_wake) + this->wake(&wake_q, this); + else + requeue_futex(this, hb1, hb2, &key2); + continue; + } + + /* Ensure we requeue to the expected futex for requeue_pi. */ + if (!futex_match(this->requeue_pi_key, &key2)) { + ret = -EINVAL; + break; + } - ret = rt_mutex_start_proxy_lock(&pi_state->pi_mutex, - this->rt_waiter, - this->task); - - if (ret == 1) { - /* - * We got the lock. We do neither drop the refcount - * on pi_state nor clear this->pi_state because the - * waiter needs the pi_state for cleaning up the - * user space value. It will drop the refcount - * after doing so. this::requeue_state is updated - * in the wakeup as well. - */ - requeue_pi_wake_futex(this, &key2, hb2); - task_count++; - } else if (!ret) { - /* Waiter is queued, move it to hb2 */ - requeue_futex(this, hb1, hb2, &key2); - futex_requeue_pi_complete(this, 0); - task_count++; - } else { /* - * rt_mutex_start_proxy_lock() detected a potential - * deadlock when we tried to queue that waiter. - * Drop the pi_state reference which we took above - * and remove the pointer to the state from the - * waiters futex_q object. + * Requeue nr_requeue waiters and possibly one more in the case + * of requeue_pi if we couldn't acquire the lock atomically. + * + * Prepare the waiter to take the rt_mutex. Take a refcount + * on the pi_state and store the pointer in the futex_q + * object of the waiter. */ - this->pi_state = NULL; - put_pi_state(pi_state); - futex_requeue_pi_complete(this, ret); - /* - * We stop queueing more waiters and let user space - * deal with the mess. - */ - break; + get_pi_state(pi_state); + + /* Don't requeue when the waiter is already on the way out. */ + if (!futex_requeue_pi_prepare(this, pi_state)) { + /* + * Early woken waiter signaled that it is on the + * way out. Drop the pi_state reference and try the + * next waiter. @this->pi_state is still NULL. + */ + put_pi_state(pi_state); + continue; + } + + ret = rt_mutex_start_proxy_lock(&pi_state->pi_mutex, + this->rt_waiter, + this->task); + + if (ret == 1) { + /* + * We got the lock. We do neither drop the refcount + * on pi_state nor clear this->pi_state because the + * waiter needs the pi_state for cleaning up the + * user space value. It will drop the refcount + * after doing so. this::requeue_state is updated + * in the wakeup as well. + */ + requeue_pi_wake_futex(this, &key2, hb2); + task_count++; + } else if (!ret) { + /* Waiter is queued, move it to hb2 */ + requeue_futex(this, hb1, hb2, &key2); + futex_requeue_pi_complete(this, 0); + task_count++; + } else { + /* + * rt_mutex_start_proxy_lock() detected a potential + * deadlock when we tried to queue that waiter. + * Drop the pi_state reference which we took above + * and remove the pointer to the state from the + * waiters futex_q object. + */ + this->pi_state = NULL; + put_pi_state(pi_state); + futex_requeue_pi_complete(this, ret); + /* + * We stop queueing more waiters and let user space + * deal with the mess. + */ + break; + } } - } - /* - * We took an extra initial reference to the pi_state in - * futex_proxy_trylock_atomic(). We need to drop it here again. - */ - put_pi_state(pi_state); + /* + * We took an extra initial reference to the pi_state in + * futex_proxy_trylock_atomic(). We need to drop it here again. + */ + put_pi_state(pi_state); out_unlock: - double_unlock_hb(hb1, hb2); + futex_hb_waiters_dec(hb2); + double_unlock_hb(hb1, hb2); + } wake_up_q(&wake_q); - futex_hb_waiters_dec(hb2); return ret ? ret : task_count; } @@ -769,7 +780,6 @@ int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, { struct hrtimer_sleeper timeout, *to; struct rt_mutex_waiter rt_waiter; - struct futex_hash_bucket *hb; union futex_key key2 = FUTEX_KEY_INIT; struct futex_q q = futex_q_init; struct rt_mutex_base *pi_mutex; @@ -805,35 +815,28 @@ int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, * Prepare to wait on uaddr. On success, it holds hb->lock and q * is initialized. */ - ret = futex_wait_setup(uaddr, val, flags, &q, &hb); + ret = futex_wait_setup(uaddr, val, flags, &q, &key2, current); if (ret) goto out; - /* - * The check above which compares uaddrs is not sufficient for - * shared futexes. We need to compare the keys: - */ - if (futex_match(&q.key, &key2)) { - futex_q_unlock(hb); - ret = -EINVAL; - goto out; - } - /* Queue the futex_q, drop the hb lock, wait for wakeup. */ - futex_wait_queue(hb, &q, to); + futex_do_wait(&q, to); switch (futex_requeue_pi_wakeup_sync(&q)) { case Q_REQUEUE_PI_IGNORE: - /* The waiter is still on uaddr1 */ - spin_lock(&hb->lock); - ret = handle_early_requeue_pi_wakeup(hb, &q, to); - spin_unlock(&hb->lock); + { + CLASS(hb, hb)(&q.key); + /* The waiter is still on uaddr1 */ + spin_lock(&hb->lock); + ret = handle_early_requeue_pi_wakeup(hb, &q, to); + spin_unlock(&hb->lock); + } break; case Q_REQUEUE_PI_LOCKED: /* The requeue acquired the lock */ if (q.pi_state && (q.pi_state->owner != current)) { - spin_lock(q.lock_ptr); + futex_q_lockptr_lock(&q); ret = fixup_pi_owner(uaddr2, &q, true); /* * Drop the reference to the pi state which the @@ -860,7 +863,7 @@ int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, if (ret && !rt_mutex_cleanup_proxy_lock(pi_mutex, &rt_waiter)) ret = 0; - spin_lock(q.lock_ptr); + futex_q_lockptr_lock(&q); debug_rt_mutex_free_waiter(&rt_waiter); /* * Fixup the pi_state owner and possibly acquire the lock if we @@ -892,6 +895,11 @@ int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, default: BUG(); } + if (q.drop_hb_ref) { + CLASS(hb, hb)(&q.key); + /* Additional reference from requeue_pi_wake_futex() */ + futex_hash_put(hb); + } out: if (to) { diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c index 25877d4f2f8f3f..e2bbe5509ec27a 100644 --- a/kernel/futex/waitwake.c +++ b/kernel/futex/waitwake.c @@ -154,7 +154,6 @@ void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q) */ int futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset) { - struct futex_hash_bucket *hb; struct futex_q *this, *next; union futex_key key = FUTEX_KEY_INIT; DEFINE_WAKE_Q(wake_q); @@ -170,7 +169,7 @@ int futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset) if ((flags & FLAGS_STRICT) && !nr_wake) return 0; - hb = futex_hash(&key); + CLASS(hb, hb)(&key); /* Make sure we really have tasks to wakeup */ if (!futex_hb_waiters_pending(hb)) @@ -253,7 +252,6 @@ int futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2, int nr_wake, int nr_wake2, int op) { union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT; - struct futex_hash_bucket *hb1, *hb2; struct futex_q *this, *next; int ret, op_ret; DEFINE_WAKE_Q(wake_q); @@ -266,67 +264,69 @@ retry: if (unlikely(ret != 0)) return ret; - hb1 = futex_hash(&key1); - hb2 = futex_hash(&key2); - retry_private: - double_lock_hb(hb1, hb2); - op_ret = futex_atomic_op_inuser(op, uaddr2); - if (unlikely(op_ret < 0)) { - double_unlock_hb(hb1, hb2); - - if (!IS_ENABLED(CONFIG_MMU) || - unlikely(op_ret != -EFAULT && op_ret != -EAGAIN)) { - /* - * we don't get EFAULT from MMU faults if we don't have - * an MMU, but we might get them from range checking - */ - ret = op_ret; - return ret; - } - - if (op_ret == -EFAULT) { - ret = fault_in_user_writeable(uaddr2); - if (ret) + if (1) { + CLASS(hb, hb1)(&key1); + CLASS(hb, hb2)(&key2); + + double_lock_hb(hb1, hb2); + op_ret = futex_atomic_op_inuser(op, uaddr2); + if (unlikely(op_ret < 0)) { + double_unlock_hb(hb1, hb2); + + if (!IS_ENABLED(CONFIG_MMU) || + unlikely(op_ret != -EFAULT && op_ret != -EAGAIN)) { + /* + * we don't get EFAULT from MMU faults if we don't have + * an MMU, but we might get them from range checking + */ + ret = op_ret; return ret; - } - - cond_resched(); - if (!(flags & FLAGS_SHARED)) - goto retry_private; - goto retry; - } + } - plist_for_each_entry_safe(this, next, &hb1->chain, list) { - if (futex_match (&this->key, &key1)) { - if (this->pi_state || this->rt_waiter) { - ret = -EINVAL; - goto out_unlock; + if (op_ret == -EFAULT) { + ret = fault_in_user_writeable(uaddr2); + if (ret) + return ret; } - this->wake(&wake_q, this); - if (++ret >= nr_wake) - break; + + cond_resched(); + if (!(flags & FLAGS_SHARED)) + goto retry_private; + goto retry; } - } - if (op_ret > 0) { - op_ret = 0; - plist_for_each_entry_safe(this, next, &hb2->chain, list) { - if (futex_match (&this->key, &key2)) { + plist_for_each_entry_safe(this, next, &hb1->chain, list) { + if (futex_match(&this->key, &key1)) { if (this->pi_state || this->rt_waiter) { ret = -EINVAL; goto out_unlock; } this->wake(&wake_q, this); - if (++op_ret >= nr_wake2) + if (++ret >= nr_wake) break; } } - ret += op_ret; - } + + if (op_ret > 0) { + op_ret = 0; + plist_for_each_entry_safe(this, next, &hb2->chain, list) { + if (futex_match(&this->key, &key2)) { + if (this->pi_state || this->rt_waiter) { + ret = -EINVAL; + goto out_unlock; + } + this->wake(&wake_q, this); + if (++op_ret >= nr_wake2) + break; + } + } + ret += op_ret; + } out_unlock: - double_unlock_hb(hb1, hb2); + double_unlock_hb(hb1, hb2); + } wake_up_q(&wake_q); return ret; } @@ -334,23 +334,12 @@ out_unlock: static long futex_wait_restart(struct restart_block *restart); /** - * futex_wait_queue() - futex_queue() and wait for wakeup, timeout, or signal - * @hb: the futex hash bucket, must be locked by the caller + * futex_do_wait() - wait for wakeup, timeout, or signal * @q: the futex_q to queue up on * @timeout: the prepared hrtimer_sleeper, or null for no timeout */ -void futex_wait_queue(struct futex_hash_bucket *hb, struct futex_q *q, - struct hrtimer_sleeper *timeout) +void futex_do_wait(struct futex_q *q, struct hrtimer_sleeper *timeout) { - /* - * The task state is guaranteed to be set before another task can - * wake it. set_current_state() is implemented using smp_store_mb() and - * futex_queue() calls spin_unlock() upon completion, both serializing - * access to the hash list and forcing another memory barrier. - */ - set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE); - futex_queue(q, hb, current); - /* Arm the timer */ if (timeout) hrtimer_sleeper_start_expires(timeout, HRTIMER_MODE_ABS); @@ -412,12 +401,17 @@ int futex_unqueue_multiple(struct futex_vector *v, int count) */ int futex_wait_multiple_setup(struct futex_vector *vs, int count, int *woken) { - struct futex_hash_bucket *hb; bool retry = false; int ret, i; u32 uval; /* + * Make sure to have a reference on the private_hash such that we + * don't block on rehash after changing the task state below. + */ + guard(private_hash)(); + + /* * Enqueuing multiple futexes is tricky, because we need to enqueue * each futex on the list before dealing with the next one to avoid * deadlocking on the hash bucket. But, before enqueuing, we need to @@ -451,20 +445,24 @@ retry: struct futex_q *q = &vs[i].q; u32 val = vs[i].w.val; - hb = futex_q_lock(q); - ret = futex_get_value_locked(&uval, uaddr); + if (1) { + CLASS(hb, hb)(&q->key); - if (!ret && uval == val) { - /* - * The bucket lock can't be held while dealing with the - * next futex. Queue each futex at this moment so hb can - * be unlocked. - */ - futex_queue(q, hb, current); - continue; - } + futex_q_lock(q, hb); + ret = futex_get_value_locked(&uval, uaddr); + + if (!ret && uval == val) { + /* + * The bucket lock can't be held while dealing with the + * next futex. Queue each futex at this moment so hb can + * be unlocked. + */ + futex_queue(q, hb, current); + continue; + } - futex_q_unlock(hb); + futex_q_unlock(hb); + } __set_current_state(TASK_RUNNING); /* @@ -578,7 +576,8 @@ int futex_wait_multiple(struct futex_vector *vs, unsigned int count, * @val: the expected value * @flags: futex flags (FLAGS_SHARED, etc.) * @q: the associated futex_q - * @hb: storage for hash_bucket pointer to be returned to caller + * @key2: the second futex_key if used for requeue PI + * @task: Task queueing this futex * * Setup the futex_q and locate the hash_bucket. Get the futex value and * compare it with the expected value. Handle atomic faults internally. @@ -586,10 +585,12 @@ int futex_wait_multiple(struct futex_vector *vs, unsigned int count, * * Return: * - 0 - uaddr contains val and hb has been locked; - * - <1 - -EFAULT or -EWOULDBLOCK (uaddr does not contain val) and hb is unlocked + * - <0 - On error and the hb is unlocked. A possible reason: the uaddr can not + * be read, does not contain the expected value or is not properly aligned. */ int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags, - struct futex_q *q, struct futex_hash_bucket **hb) + struct futex_q *q, union futex_key *key2, + struct task_struct *task) { u32 uval; int ret; @@ -618,26 +619,45 @@ retry: return ret; retry_private: - *hb = futex_q_lock(q); + if (1) { + CLASS(hb, hb)(&q->key); - ret = futex_get_value_locked(&uval, uaddr); + futex_q_lock(q, hb); - if (ret) { - futex_q_unlock(*hb); + ret = futex_get_value_locked(&uval, uaddr); - ret = get_user(uval, uaddr); - if (ret) - return ret; + if (ret) { + futex_q_unlock(hb); - if (!(flags & FLAGS_SHARED)) - goto retry_private; + ret = get_user(uval, uaddr); + if (ret) + return ret; - goto retry; - } + if (!(flags & FLAGS_SHARED)) + goto retry_private; + + goto retry; + } - if (uval != val) { - futex_q_unlock(*hb); - ret = -EWOULDBLOCK; + if (uval != val) { + futex_q_unlock(hb); + return -EWOULDBLOCK; + } + + if (key2 && futex_match(&q->key, key2)) { + futex_q_unlock(hb); + return -EINVAL; + } + + /* + * The task state is guaranteed to be set before another task can + * wake it. set_current_state() is implemented using smp_store_mb() and + * futex_queue() calls spin_unlock() upon completion, both serializing + * access to the hash list and forcing another memory barrier. + */ + if (task == current) + set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE); + futex_queue(q, hb, task); } return ret; @@ -647,7 +667,6 @@ int __futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, struct hrtimer_sleeper *to, u32 bitset) { struct futex_q q = futex_q_init; - struct futex_hash_bucket *hb; int ret; if (!bitset) @@ -660,12 +679,12 @@ retry: * Prepare to wait on uaddr. On success, it holds hb->lock and q * is initialized. */ - ret = futex_wait_setup(uaddr, val, flags, &q, &hb); + ret = futex_wait_setup(uaddr, val, flags, &q, NULL, current); if (ret) return ret; /* futex_queue and wait for wakeup, timeout, or a signal. */ - futex_wait_queue(hb, &q, to); + futex_do_wait(&q, to); /* If we were woken (and unqueued), we succeeded, whatever. */ if (!futex_unqueue(&q)) diff --git a/kernel/sys.c b/kernel/sys.c index c434968e9f5dd6..adc0de0aa364ae 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -52,6 +52,7 @@ #include <linux/user_namespace.h> #include <linux/time_namespace.h> #include <linux/binfmts.h> +#include <linux/futex.h> #include <linux/sched.h> #include <linux/sched/autogroup.h> @@ -2820,6 +2821,9 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, return -EINVAL; error = posixtimer_create_prctl(arg2); break; + case PR_FUTEX_HASH: + error = futex_hash_prctl(arg2, arg3, arg4); + break; default: trace_task_prctl_unknown(option, arg2, arg3, arg4, arg5); error = -EINVAL; diff --git a/mm/nommu.c b/mm/nommu.c index 617e7ba8022f5b..70f92f9a7fab3b 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -200,7 +200,23 @@ void *vmalloc_noprof(unsigned long size) } EXPORT_SYMBOL(vmalloc_noprof); -void *vmalloc_huge_noprof(unsigned long size, gfp_t gfp_mask) __weak __alias(__vmalloc_noprof); +/* + * vmalloc_huge_node - allocate virtually contiguous memory, on a node + * + * @size: allocation size + * @gfp_mask: flags for the page level allocator + * @node: node to use for allocation or NUMA_NO_NODE + * + * Allocate enough pages to cover @size from the page level + * allocator and map them into contiguous kernel virtual space. + * + * Due to NOMMU implications the node argument and HUGE page attribute is + * ignored. + */ +void *vmalloc_huge_node_noprof(unsigned long size, gfp_t gfp_mask, int node) +{ + return __vmalloc_noprof(size, gfp_mask); +} /* * vzalloc - allocate virtually contiguous memory with zero fill diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 3ed720a787ecd8..8b9f6d3c099dd5 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3943,9 +3943,10 @@ void *vmalloc_noprof(unsigned long size) EXPORT_SYMBOL(vmalloc_noprof); /** - * vmalloc_huge - allocate virtually contiguous memory, allow huge pages + * vmalloc_huge_node - allocate virtually contiguous memory, allow huge pages * @size: allocation size * @gfp_mask: flags for the page level allocator + * @node: node to use for allocation or NUMA_NO_NODE * * Allocate enough pages to cover @size from the page level * allocator and map them into contiguous kernel virtual space. @@ -3954,13 +3955,13 @@ EXPORT_SYMBOL(vmalloc_noprof); * * Return: pointer to the allocated memory or %NULL on error */ -void *vmalloc_huge_noprof(unsigned long size, gfp_t gfp_mask) +void *vmalloc_huge_node_noprof(unsigned long size, gfp_t gfp_mask, int node) { return __vmalloc_node_range_noprof(size, 1, VMALLOC_START, VMALLOC_END, - gfp_mask, PAGE_KERNEL, VM_ALLOW_HUGE_VMAP, - NUMA_NO_NODE, __builtin_return_address(0)); + gfp_mask, PAGE_KERNEL, VM_ALLOW_HUGE_VMAP, + node, __builtin_return_address(0)); } -EXPORT_SYMBOL_GPL(vmalloc_huge_noprof); +EXPORT_SYMBOL_GPL(vmalloc_huge_node_noprof); /** * vzalloc - allocate virtually contiguous memory with zero fill diff --git a/tools/include/uapi/linux/prctl.h b/tools/include/uapi/linux/prctl.h index 35791791a879b2..43dec6eed559a6 100644 --- a/tools/include/uapi/linux/prctl.h +++ b/tools/include/uapi/linux/prctl.h @@ -230,7 +230,7 @@ struct prctl_mm_map { # define PR_PAC_APDBKEY (1UL << 3) # define PR_PAC_APGAKEY (1UL << 4) -/* Tagged user address controls for arm64 */ +/* Tagged user address controls for arm64 and RISC-V */ #define PR_SET_TAGGED_ADDR_CTRL 55 #define PR_GET_TAGGED_ADDR_CTRL 56 # define PR_TAGGED_ADDR_ENABLE (1UL << 0) @@ -244,6 +244,9 @@ struct prctl_mm_map { # define PR_MTE_TAG_MASK (0xffffUL << PR_MTE_TAG_SHIFT) /* Unused; kept only for source compatibility */ # define PR_MTE_TCF_SHIFT 1 +/* RISC-V pointer masking tag length */ +# define PR_PMLEN_SHIFT 24 +# define PR_PMLEN_MASK (0x7fUL << PR_PMLEN_SHIFT) /* Control reclaim behavior when allocating memory */ #define PR_SET_IO_FLUSHER 57 @@ -328,4 +331,44 @@ struct prctl_mm_map { # define PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC 0x10 /* Clear the aspect on exec */ # define PR_PPC_DEXCR_CTRL_MASK 0x1f +/* + * Get the current shadow stack configuration for the current thread, + * this will be the value configured via PR_SET_SHADOW_STACK_STATUS. + */ +#define PR_GET_SHADOW_STACK_STATUS 74 + +/* + * Set the current shadow stack configuration. Enabling the shadow + * stack will cause a shadow stack to be allocated for the thread. + */ +#define PR_SET_SHADOW_STACK_STATUS 75 +# define PR_SHADOW_STACK_ENABLE (1UL << 0) +# define PR_SHADOW_STACK_WRITE (1UL << 1) +# define PR_SHADOW_STACK_PUSH (1UL << 2) + +/* + * Prevent further changes to the specified shadow stack + * configuration. All bits may be locked via this call, including + * undefined bits. + */ +#define PR_LOCK_SHADOW_STACK_STATUS 76 + +/* + * Controls the mode of timer_create() for CRIU restore operations. + * Enabling this allows CRIU to restore timers with explicit IDs. + * + * Don't use for normal operations as the result might be undefined. + */ +#define PR_TIMER_CREATE_RESTORE_IDS 77 +# define PR_TIMER_CREATE_RESTORE_IDS_OFF 0 +# define PR_TIMER_CREATE_RESTORE_IDS_ON 1 +# define PR_TIMER_CREATE_RESTORE_IDS_GET 2 + +/* FUTEX hash management */ +#define PR_FUTEX_HASH 78 +# define PR_FUTEX_HASH_SET_SLOTS 1 +# define FH_FLAG_IMMUTABLE (1ULL << 0) +# define PR_FUTEX_HASH_GET_SLOTS 2 +# define PR_FUTEX_HASH_GET_IMMUTABLE 3 + #endif /* _LINUX_PRCTL_H */ diff --git a/tools/perf/bench/Build b/tools/perf/bench/Build index 279ab2ab4abe42..b558ab98719f92 100644 --- a/tools/perf/bench/Build +++ b/tools/perf/bench/Build @@ -3,6 +3,7 @@ perf-bench-y += sched-pipe.o perf-bench-y += sched-seccomp-notify.o perf-bench-y += syscall.o perf-bench-y += mem-functions.o +perf-bench-y += futex.o perf-bench-y += futex-hash.o perf-bench-y += futex-wake.o perf-bench-y += futex-wake-parallel.o diff --git a/tools/perf/bench/futex-hash.c b/tools/perf/bench/futex-hash.c index b472eded521b1c..fdf133c9520f73 100644 --- a/tools/perf/bench/futex-hash.c +++ b/tools/perf/bench/futex-hash.c @@ -18,9 +18,11 @@ #include <stdlib.h> #include <linux/compiler.h> #include <linux/kernel.h> +#include <linux/prctl.h> #include <linux/zalloc.h> #include <sys/time.h> #include <sys/mman.h> +#include <sys/prctl.h> #include <perf/cpumap.h> #include "../util/mutex.h" @@ -50,9 +52,12 @@ struct worker { static struct bench_futex_parameters params = { .nfutexes = 1024, .runtime = 10, + .nbuckets = -1, }; static const struct option options[] = { + OPT_INTEGER( 'b', "buckets", ¶ms.nbuckets, "Specify amount of hash buckets"), + OPT_BOOLEAN( 'I', "immutable", ¶ms.buckets_immutable, "Make the hash buckets immutable"), OPT_UINTEGER('t', "threads", ¶ms.nthreads, "Specify amount of threads"), OPT_UINTEGER('r', "runtime", ¶ms.runtime, "Specify runtime (in seconds)"), OPT_UINTEGER('f', "futexes", ¶ms.nfutexes, "Specify amount of futexes per threads"), @@ -118,6 +123,7 @@ static void print_summary(void) printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n", !params.silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg), (int)bench__runtime.tv_sec); + futex_print_nbuckets(¶ms); } int bench_futex_hash(int argc, const char **argv) @@ -161,6 +167,7 @@ int bench_futex_hash(int argc, const char **argv) if (!params.fshared) futex_flag = FUTEX_PRIVATE_FLAG; + futex_set_nbuckets_param(¶ms); printf("Run summary [PID %d]: %d threads, each operating on %d [%s] futexes for %d secs.\n\n", getpid(), params.nthreads, params.nfutexes, params.fshared ? "shared":"private", params.runtime); diff --git a/tools/perf/bench/futex-lock-pi.c b/tools/perf/bench/futex-lock-pi.c index 0416120c091b24..5144a158512cc8 100644 --- a/tools/perf/bench/futex-lock-pi.c +++ b/tools/perf/bench/futex-lock-pi.c @@ -41,10 +41,13 @@ static struct stats throughput_stats; static struct cond thread_parent, thread_worker; static struct bench_futex_parameters params = { + .nbuckets = -1, .runtime = 10, }; static const struct option options[] = { + OPT_INTEGER( 'b', "buckets", ¶ms.nbuckets, "Specify amount of hash buckets"), + OPT_BOOLEAN( 'I', "immutable", ¶ms.buckets_immutable, "Make the hash buckets immutable"), OPT_UINTEGER('t', "threads", ¶ms.nthreads, "Specify amount of threads"), OPT_UINTEGER('r', "runtime", ¶ms.runtime, "Specify runtime (in seconds)"), OPT_BOOLEAN( 'M', "multi", ¶ms.multi, "Use multiple futexes"), @@ -67,6 +70,7 @@ static void print_summary(void) printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n", !params.silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg), (int)bench__runtime.tv_sec); + futex_print_nbuckets(¶ms); } static void toggle_done(int sig __maybe_unused, @@ -203,6 +207,7 @@ int bench_futex_lock_pi(int argc, const char **argv) mutex_init(&thread_lock); cond_init(&thread_parent); cond_init(&thread_worker); + futex_set_nbuckets_param(¶ms); threads_starting = params.nthreads; gettimeofday(&bench__start, NULL); diff --git a/tools/perf/bench/futex-requeue.c b/tools/perf/bench/futex-requeue.c index aad5bfc4fe188d..a2f91ee1950b34 100644 --- a/tools/perf/bench/futex-requeue.c +++ b/tools/perf/bench/futex-requeue.c @@ -42,6 +42,7 @@ static unsigned int threads_starting; static int futex_flag = 0; static struct bench_futex_parameters params = { + .nbuckets = -1, /* * How many tasks to requeue at a time. * Default to 1 in order to make the kernel work more. @@ -50,6 +51,8 @@ static struct bench_futex_parameters params = { }; static const struct option options[] = { + OPT_INTEGER( 'b', "buckets", ¶ms.nbuckets, "Specify amount of hash buckets"), + OPT_BOOLEAN( 'I', "immutable", ¶ms.buckets_immutable, "Make the hash buckets immutable"), OPT_UINTEGER('t', "threads", ¶ms.nthreads, "Specify amount of threads"), OPT_UINTEGER('q', "nrequeue", ¶ms.nrequeue, "Specify amount of threads to requeue at once"), OPT_BOOLEAN( 's', "silent", ¶ms.silent, "Silent mode: do not display data/details"), @@ -77,6 +80,7 @@ static void print_summary(void) params.nthreads, requeuetime_avg / USEC_PER_MSEC, rel_stddev_stats(requeuetime_stddev, requeuetime_avg)); + futex_print_nbuckets(¶ms); } static void *workerfn(void *arg __maybe_unused) @@ -204,6 +208,8 @@ int bench_futex_requeue(int argc, const char **argv) if (params.broadcast) params.nrequeue = params.nthreads; + futex_set_nbuckets_param(¶ms); + printf("Run summary [PID %d]: Requeuing %d threads (from [%s] %p to %s%p), " "%d at a time.\n\n", getpid(), params.nthreads, params.fshared ? "shared":"private", &futex1, diff --git a/tools/perf/bench/futex-wake-parallel.c b/tools/perf/bench/futex-wake-parallel.c index 4352e318631e99..ee66482c29fd1c 100644 --- a/tools/perf/bench/futex-wake-parallel.c +++ b/tools/perf/bench/futex-wake-parallel.c @@ -57,9 +57,13 @@ static struct stats waketime_stats, wakeup_stats; static unsigned int threads_starting; static int futex_flag = 0; -static struct bench_futex_parameters params; +static struct bench_futex_parameters params = { + .nbuckets = -1, +}; static const struct option options[] = { + OPT_INTEGER( 'b', "buckets", ¶ms.nbuckets, "Specify amount of hash buckets"), + OPT_BOOLEAN( 'I', "immutable", ¶ms.buckets_immutable, "Make the hash buckets immutable"), OPT_UINTEGER('t', "threads", ¶ms.nthreads, "Specify amount of threads"), OPT_UINTEGER('w', "nwakers", ¶ms.nwakes, "Specify amount of waking threads"), OPT_BOOLEAN( 's', "silent", ¶ms.silent, "Silent mode: do not display data/details"), @@ -218,6 +222,7 @@ static void print_summary(void) params.nthreads, waketime_avg / USEC_PER_MSEC, rel_stddev_stats(waketime_stddev, waketime_avg)); + futex_print_nbuckets(¶ms); } @@ -291,6 +296,8 @@ int bench_futex_wake_parallel(int argc, const char **argv) if (!params.fshared) futex_flag = FUTEX_PRIVATE_FLAG; + futex_set_nbuckets_param(¶ms); + printf("Run summary [PID %d]: blocking on %d threads (at [%s] " "futex %p), %d threads waking up %d at a time.\n\n", getpid(), params.nthreads, params.fshared ? "shared":"private", diff --git a/tools/perf/bench/futex-wake.c b/tools/perf/bench/futex-wake.c index 49b3c89b0b35d6..8d6107f7cd9410 100644 --- a/tools/perf/bench/futex-wake.c +++ b/tools/perf/bench/futex-wake.c @@ -42,6 +42,7 @@ static unsigned int threads_starting; static int futex_flag = 0; static struct bench_futex_parameters params = { + .nbuckets = -1, /* * How many wakeups to do at a time. * Default to 1 in order to make the kernel work more. @@ -50,6 +51,8 @@ static struct bench_futex_parameters params = { }; static const struct option options[] = { + OPT_INTEGER( 'b', "buckets", ¶ms.nbuckets, "Specify amount of hash buckets"), + OPT_BOOLEAN( 'I', "immutable", ¶ms.buckets_immutable, "Make the hash buckets immutable"), OPT_UINTEGER('t', "threads", ¶ms.nthreads, "Specify amount of threads"), OPT_UINTEGER('w', "nwakes", ¶ms.nwakes, "Specify amount of threads to wake at once"), OPT_BOOLEAN( 's', "silent", ¶ms.silent, "Silent mode: do not display data/details"), @@ -93,6 +96,7 @@ static void print_summary(void) params.nthreads, waketime_avg / USEC_PER_MSEC, rel_stddev_stats(waketime_stddev, waketime_avg)); + futex_print_nbuckets(¶ms); } static void block_threads(pthread_t *w, struct perf_cpu_map *cpu) diff --git a/tools/perf/bench/futex.c b/tools/perf/bench/futex.c new file mode 100644 index 00000000000000..26382e4d8d4ce2 --- /dev/null +++ b/tools/perf/bench/futex.c @@ -0,0 +1,67 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <err.h> +#include <stdio.h> +#include <stdlib.h> +#include <linux/prctl.h> +#include <sys/prctl.h> + +#include "futex.h" + +void futex_set_nbuckets_param(struct bench_futex_parameters *params) +{ + unsigned long flags; + int ret; + + if (params->nbuckets < 0) + return; + + flags = params->buckets_immutable ? FH_FLAG_IMMUTABLE : 0; + ret = prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_SET_SLOTS, params->nbuckets, flags); + if (ret) { + printf("Requesting %d hash buckets failed: %d/%m\n", + params->nbuckets, ret); + err(EXIT_FAILURE, "prctl(PR_FUTEX_HASH)"); + } +} + +void futex_print_nbuckets(struct bench_futex_parameters *params) +{ + char *futex_hash_mode; + int ret; + + ret = prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_GET_SLOTS); + if (params->nbuckets >= 0) { + if (ret != params->nbuckets) { + if (ret < 0) { + printf("Can't query number of buckets: %m\n"); + err(EXIT_FAILURE, "prctl(PR_FUTEX_HASH)"); + } + printf("Requested number of hash buckets does not currently used.\n"); + printf("Requested: %d in usage: %d\n", params->nbuckets, ret); + err(EXIT_FAILURE, "prctl(PR_FUTEX_HASH)"); + } + if (params->nbuckets == 0) { + ret = asprintf(&futex_hash_mode, "Futex hashing: global hash"); + } else { + ret = prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_GET_IMMUTABLE); + if (ret < 0) { + printf("Can't check if the hash is immutable: %m\n"); + err(EXIT_FAILURE, "prctl(PR_FUTEX_HASH)"); + } + ret = asprintf(&futex_hash_mode, "Futex hashing: %d hash buckets %s", + params->nbuckets, + ret == 1 ? "(immutable)" : ""); + } + } else { + if (ret <= 0) { + ret = asprintf(&futex_hash_mode, "Futex hashing: global hash"); + } else { + ret = asprintf(&futex_hash_mode, "Futex hashing: auto resized to %d buckets", + ret); + } + } + if (ret < 0) + err(EXIT_FAILURE, "ENOMEM, futex_hash_mode"); + printf("%s\n", futex_hash_mode); + free(futex_hash_mode); +} diff --git a/tools/perf/bench/futex.h b/tools/perf/bench/futex.h index ebdc2b032afc16..9c9a73f9d865e7 100644 --- a/tools/perf/bench/futex.h +++ b/tools/perf/bench/futex.h @@ -25,6 +25,8 @@ struct bench_futex_parameters { unsigned int nfutexes; unsigned int nwakes; unsigned int nrequeue; + int nbuckets; + bool buckets_immutable; }; /** @@ -143,4 +145,7 @@ futex_cmp_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, val, opflags); } +void futex_set_nbuckets_param(struct bench_futex_parameters *params); +void futex_print_nbuckets(struct bench_futex_parameters *params); + #endif /* _FUTEX_H */ diff --git a/tools/testing/selftests/futex/functional/.gitignore b/tools/testing/selftests/futex/functional/.gitignore index fbcbdb6963b3a6..7b24ae89594a9d 100644 --- a/tools/testing/selftests/futex/functional/.gitignore +++ b/tools/testing/selftests/futex/functional/.gitignore @@ -1,11 +1,13 @@ # SPDX-License-Identifier: GPL-2.0-only +futex_numa_mpol +futex_priv_hash +futex_requeue futex_requeue_pi futex_requeue_pi_mismatched_ops futex_requeue_pi_signal_restart +futex_wait futex_wait_private_mapped_file futex_wait_timeout futex_wait_uninitialized_heap futex_wait_wouldblock -futex_wait -futex_requeue futex_waitv diff --git a/tools/testing/selftests/futex/functional/Makefile b/tools/testing/selftests/futex/functional/Makefile index f79f9bac7918bc..8cfb87f7f7c505 100644 --- a/tools/testing/selftests/futex/functional/Makefile +++ b/tools/testing/selftests/futex/functional/Makefile @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 INCLUDES := -I../include -I../../ $(KHDR_INCLUDES) CFLAGS := $(CFLAGS) -g -O2 -Wall -pthread $(INCLUDES) $(KHDR_INCLUDES) -LDLIBS := -lpthread -lrt +LDLIBS := -lpthread -lrt -lnuma LOCAL_HDRS := \ ../include/futextest.h \ @@ -17,7 +17,10 @@ TEST_GEN_PROGS := \ futex_wait_private_mapped_file \ futex_wait \ futex_requeue \ - futex_waitv + futex_priv_hash \ + futex_numa_mpol \ + futex_waitv \ + futex_numa TEST_PROGS := run.sh diff --git a/tools/testing/selftests/futex/functional/futex_numa.c b/tools/testing/selftests/futex/functional/futex_numa.c new file mode 100644 index 00000000000000..f29e4d627e7942 --- /dev/null +++ b/tools/testing/selftests/futex/functional/futex_numa.c @@ -0,0 +1,262 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <pthread.h> +#include <sys/shm.h> +#include <sys/mman.h> +#include <fcntl.h> +#include <stdbool.h> +#include <time.h> +#include <assert.h> +#include "logging.h" +#include "futextest.h" +#include "futex2test.h" + +typedef u_int32_t u32; +typedef int32_t s32; +typedef u_int64_t u64; + +static unsigned int fflags = (FUTEX2_SIZE_U32 | FUTEX2_PRIVATE); +static int fnode = FUTEX_NO_NODE; + +/* fairly stupid test-and-set lock with a waiter flag */ + +#define N_LOCK 0x0000001 +#define N_WAITERS 0x0001000 + +struct futex_numa_32 { + union { + u64 full; + struct { + u32 val; + u32 node; + }; + }; +}; + +void futex_numa_32_lock(struct futex_numa_32 *lock) +{ + for (;;) { + struct futex_numa_32 new, old = { + .full = __atomic_load_n(&lock->full, __ATOMIC_RELAXED), + }; + + for (;;) { + new = old; + if (old.val == 0) { + /* no waiter, no lock -> first lock, set no-node */ + new.node = fnode; + } + if (old.val & N_LOCK) { + /* contention, set waiter */ + new.val |= N_WAITERS; + } + new.val |= N_LOCK; + + /* nothing changed, ready to block */ + if (old.full == new.full) + break; + + /* + * Use u64 cmpxchg to set the futex value and node in a + * consistent manner. + */ + if (__atomic_compare_exchange_n(&lock->full, + &old.full, new.full, + /* .weak */ false, + __ATOMIC_ACQUIRE, + __ATOMIC_RELAXED)) { + + /* if we just set N_LOCK, we own it */ + if (!(old.val & N_LOCK)) + return; + + /* go block */ + break; + } + } + + futex2_wait(lock, new.val, fflags, NULL, 0); + } +} + +void futex_numa_32_unlock(struct futex_numa_32 *lock) +{ + u32 val = __atomic_sub_fetch(&lock->val, N_LOCK, __ATOMIC_RELEASE); + assert((s32)val >= 0); + if (val & N_WAITERS) { + int woken = futex2_wake(lock, 1, fflags); + assert(val == N_WAITERS); + if (!woken) { + __atomic_compare_exchange_n(&lock->val, &val, 0U, + false, __ATOMIC_RELAXED, + __ATOMIC_RELAXED); + } + } +} + +static long nanos = 50000; + +struct thread_args { + pthread_t tid; + volatile int * done; + struct futex_numa_32 *lock; + int val; + int *val1, *val2; + int node; +}; + +static void *threadfn(void *_arg) +{ + struct thread_args *args = _arg; + struct timespec ts = { + .tv_nsec = nanos, + }; + int node; + + while (!*args->done) { + + futex_numa_32_lock(args->lock); + args->val++; + + assert(*args->val1 == *args->val2); + (*args->val1)++; + nanosleep(&ts, NULL); + (*args->val2)++; + + node = args->lock->node; + futex_numa_32_unlock(args->lock); + + if (node != args->node) { + args->node = node; + printf("node: %d\n", node); + } + + nanosleep(&ts, NULL); + } + + return NULL; +} + +static void *contendfn(void *_arg) +{ + struct thread_args *args = _arg; + + while (!*args->done) { + /* + * futex2_wait() will take hb-lock, verify *var == val and + * queue/abort. By knowingly setting val 'wrong' this will + * abort and thereby generate hb-lock contention. + */ + futex2_wait(&args->lock->val, ~0U, fflags, NULL, 0); + args->val++; + } + + return NULL; +} + +static volatile int done = 0; +static struct futex_numa_32 lock = { .val = 0, }; +static int val1, val2; + +int main(int argc, char *argv[]) +{ + struct thread_args *tas[512], *cas[512]; + int c, t, threads = 2, contenders = 0; + int sleeps = 10; + int total = 0; + + while ((c = getopt(argc, argv, "c:t:s:n:N::")) != -1) { + switch (c) { + case 'c': + contenders = atoi(optarg); + break; + case 't': + threads = atoi(optarg); + break; + case 's': + sleeps = atoi(optarg); + break; + case 'n': + nanos = atoi(optarg); + break; + case 'N': + fflags |= FUTEX2_NUMA; + if (optarg) + fnode = atoi(optarg); + break; + default: + exit(1); + break; + } + } + + for (t = 0; t < contenders; t++) { + struct thread_args *args = calloc(1, sizeof(*args)); + if (!args) { + perror("thread_args"); + exit(-1); + } + + args->done = &done; + args->lock = &lock; + args->val1 = &val1; + args->val2 = &val2; + args->node = -1; + + if (pthread_create(&args->tid, NULL, contendfn, args)) { + perror("pthread_create"); + exit(-1); + } + + cas[t] = args; + } + + for (t = 0; t < threads; t++) { + struct thread_args *args = calloc(1, sizeof(*args)); + if (!args) { + perror("thread_args"); + exit(-1); + } + + args->done = &done; + args->lock = &lock; + args->val1 = &val1; + args->val2 = &val2; + args->node = -1; + + if (pthread_create(&args->tid, NULL, threadfn, args)) { + perror("pthread_create"); + exit(-1); + } + + tas[t] = args; + } + + sleep(sleeps); + + done = true; + + for (t = 0; t < threads; t++) { + struct thread_args *args = tas[t]; + + pthread_join(args->tid, NULL); + total += args->val; +// printf("tval: %d\n", args->val); + } + printf("total: %d\n", total); + + if (contenders) { + total = 0; + for (t = 0; t < contenders; t++) { + struct thread_args *args = cas[t]; + + pthread_join(args->tid, NULL); + total += args->val; + // printf("tval: %d\n", args->val); + } + printf("contenders: %d\n", total); + } + + return 0; +} + diff --git a/tools/testing/selftests/futex/functional/futex_numa_mpol.c b/tools/testing/selftests/futex/functional/futex_numa_mpol.c new file mode 100644 index 00000000000000..20a9d3ecf7433c --- /dev/null +++ b/tools/testing/selftests/futex/functional/futex_numa_mpol.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2025 Sebastian Andrzej Siewior <bigeasy@linutronix.de> + */ + +#define _GNU_SOURCE + +#include <errno.h> +#include <pthread.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <numa.h> +#include <numaif.h> + +#include <linux/futex.h> +#include <sys/mman.h> + +#include "logging.h" +#include "futextest.h" +#include "futex2test.h" + +#define MAX_THREADS 64 + +static pthread_barrier_t barrier_main; +static pthread_t threads[MAX_THREADS]; + +struct thread_args { + void *futex_ptr; + unsigned int flags; + int result; +}; + +static struct thread_args thread_args[MAX_THREADS]; + +#ifndef FUTEX_NO_NODE +#define FUTEX_NO_NODE (-1) +#endif + +#ifndef FUTEX2_MPOL +#define FUTEX2_MPOL 0x08 +#endif + +static void *thread_lock_fn(void *arg) +{ + struct thread_args *args = arg; + int ret; + + pthread_barrier_wait(&barrier_main); + ret = futex2_wait(args->futex_ptr, 0, args->flags, NULL, 0); + args->result = ret; + return NULL; +} + +static void create_max_threads(void *futex_ptr) +{ + int i, ret; + + for (i = 0; i < MAX_THREADS; i++) { + thread_args[i].futex_ptr = futex_ptr; + thread_args[i].flags = FUTEX2_SIZE_U32 | FUTEX_PRIVATE_FLAG | FUTEX2_NUMA; + thread_args[i].result = 0; + ret = pthread_create(&threads[i], NULL, thread_lock_fn, &thread_args[i]); + if (ret) + ksft_exit_fail_msg("pthread_create failed\n"); + } +} + +static void join_max_threads(void) +{ + int i, ret; + + for (i = 0; i < MAX_THREADS; i++) { + ret = pthread_join(threads[i], NULL); + if (ret) + ksft_exit_fail_msg("pthread_join failed for thread %d\n", i); + } +} + +static void __test_futex(void *futex_ptr, int must_fail, unsigned int futex_flags) +{ + int to_wake, ret, i, need_exit = 0; + + pthread_barrier_init(&barrier_main, NULL, MAX_THREADS + 1); + create_max_threads(futex_ptr); + pthread_barrier_wait(&barrier_main); + to_wake = MAX_THREADS; + + do { + ret = futex2_wake(futex_ptr, to_wake, futex_flags); + if (must_fail) { + if (ret < 0) + break; + ksft_exit_fail_msg("futex2_wake(%d, 0x%x) should fail, but didn't\n", + to_wake, futex_flags); + } + if (ret < 0) { + ksft_exit_fail_msg("Failed futex2_wake(%d, 0x%x): %m\n", + to_wake, futex_flags); + } + if (!ret) + usleep(50); + to_wake -= ret; + + } while (to_wake); + join_max_threads(); + + for (i = 0; i < MAX_THREADS; i++) { + if (must_fail && thread_args[i].result != -1) { + ksft_print_msg("Thread %d should fail but succeeded (%d)\n", + i, thread_args[i].result); + need_exit = 1; + } + if (!must_fail && thread_args[i].result != 0) { + ksft_print_msg("Thread %d failed (%d)\n", i, thread_args[i].result); + need_exit = 1; + } + } + if (need_exit) + ksft_exit_fail_msg("Aborting due to earlier errors.\n"); +} + +static void test_futex(void *futex_ptr, int must_fail) +{ + __test_futex(futex_ptr, must_fail, FUTEX2_SIZE_U32 | FUTEX_PRIVATE_FLAG | FUTEX2_NUMA); +} + +static void test_futex_mpol(void *futex_ptr, int must_fail) +{ + __test_futex(futex_ptr, must_fail, FUTEX2_SIZE_U32 | FUTEX_PRIVATE_FLAG | FUTEX2_NUMA | FUTEX2_MPOL); +} + +static void usage(char *prog) +{ + printf("Usage: %s\n", prog); + printf(" -c Use color\n"); + printf(" -h Display this help message\n"); + printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n", + VQUIET, VCRITICAL, VINFO); +} + +int main(int argc, char *argv[]) +{ + struct futex32_numa *futex_numa; + int mem_size, i; + void *futex_ptr; + char c; + + while ((c = getopt(argc, argv, "chv:")) != -1) { + switch (c) { + case 'c': + log_color(1); + break; + case 'h': + usage(basename(argv[0])); + exit(0); + break; + case 'v': + log_verbosity(atoi(optarg)); + break; + default: + usage(basename(argv[0])); + exit(1); + } + } + + ksft_print_header(); + ksft_set_plan(1); + + mem_size = sysconf(_SC_PAGE_SIZE); + futex_ptr = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); + if (futex_ptr == MAP_FAILED) + ksft_exit_fail_msg("mmap() for %d bytes failed\n", mem_size); + + futex_numa = futex_ptr; + + ksft_print_msg("Regular test\n"); + futex_numa->futex = 0; + futex_numa->numa = FUTEX_NO_NODE; + test_futex(futex_ptr, 0); + + if (futex_numa->numa == FUTEX_NO_NODE) + ksft_exit_fail_msg("NUMA node is left uninitialized\n"); + + ksft_print_msg("Memory too small\n"); + test_futex(futex_ptr + mem_size - 4, 1); + + ksft_print_msg("Memory out of range\n"); + test_futex(futex_ptr + mem_size, 1); + + futex_numa->numa = FUTEX_NO_NODE; + mprotect(futex_ptr, mem_size, PROT_READ); + ksft_print_msg("Memory, RO\n"); + test_futex(futex_ptr, 1); + + mprotect(futex_ptr, mem_size, PROT_NONE); + ksft_print_msg("Memory, no access\n"); + test_futex(futex_ptr, 1); + + mprotect(futex_ptr, mem_size, PROT_READ | PROT_WRITE); + ksft_print_msg("Memory back to RW\n"); + test_futex(futex_ptr, 0); + + /* MPOL test. Does not work as expected */ + for (i = 0; i < 4; i++) { + unsigned long nodemask; + int ret; + + nodemask = 1 << i; + ret = mbind(futex_ptr, mem_size, MPOL_BIND, &nodemask, + sizeof(nodemask) * 8, 0); + if (ret == 0) { + ksft_print_msg("Node %d test\n", i); + futex_numa->futex = 0; + futex_numa->numa = FUTEX_NO_NODE; + + ret = futex2_wake(futex_ptr, 0, FUTEX2_SIZE_U32 | FUTEX_PRIVATE_FLAG | FUTEX2_NUMA | FUTEX2_MPOL); + if (ret < 0) + ksft_test_result_fail("Failed to wake 0 with MPOL: %m\n"); + if (0) + test_futex_mpol(futex_numa, 0); + if (futex_numa->numa != i) { + ksft_test_result_fail("Returned NUMA node is %d expected %d\n", + futex_numa->numa, i); + } + } + } + ksft_test_result_pass("NUMA MPOL tests passed\n"); + ksft_finished(); + return 0; +} diff --git a/tools/testing/selftests/futex/functional/futex_priv_hash.c b/tools/testing/selftests/futex/functional/futex_priv_hash.c new file mode 100644 index 00000000000000..2dca18fefedcda --- /dev/null +++ b/tools/testing/selftests/futex/functional/futex_priv_hash.c @@ -0,0 +1,292 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2025 Sebastian Andrzej Siewior <bigeasy@linutronix.de> + */ + +#define _GNU_SOURCE + +#include <errno.h> +#include <pthread.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> + +#include <linux/prctl.h> +#include <sys/prctl.h> + +#include "logging.h" + +#define MAX_THREADS 64 + +static pthread_barrier_t barrier_main; +static pthread_mutex_t global_lock; +static pthread_t threads[MAX_THREADS]; +static int counter; + +#ifndef PR_FUTEX_HASH +#define PR_FUTEX_HASH 78 +# define PR_FUTEX_HASH_SET_SLOTS 1 +# define FH_FLAG_IMMUTABLE (1ULL << 0) +# define PR_FUTEX_HASH_GET_SLOTS 2 +# define PR_FUTEX_HASH_GET_IMMUTABLE 3 +#endif + +static int futex_hash_slots_set(unsigned int slots, int flags) +{ + return prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_SET_SLOTS, slots, flags); +} + +static int futex_hash_slots_get(void) +{ + return prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_GET_SLOTS); +} + +static int futex_hash_immutable_get(void) +{ + return prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_GET_IMMUTABLE); +} + +static void futex_hash_slots_set_verify(int slots) +{ + int ret; + + ret = futex_hash_slots_set(slots, 0); + if (ret != 0) { + ksft_test_result_fail("Failed to set slots to %d: %m\n", slots); + ksft_finished(); + } + ret = futex_hash_slots_get(); + if (ret != slots) { + ksft_test_result_fail("Set %d slots but PR_FUTEX_HASH_GET_SLOTS returns: %d, %m\n", + slots, ret); + ksft_finished(); + } + ksft_test_result_pass("SET and GET slots %d passed\n", slots); +} + +static void futex_hash_slots_set_must_fail(int slots, int flags) +{ + int ret; + + ret = futex_hash_slots_set(slots, flags); + ksft_test_result(ret < 0, "futex_hash_slots_set(%d, %d)\n", + slots, flags); +} + +static void *thread_return_fn(void *arg) +{ + return NULL; +} + +static void *thread_lock_fn(void *arg) +{ + pthread_barrier_wait(&barrier_main); + + pthread_mutex_lock(&global_lock); + counter++; + usleep(20); + pthread_mutex_unlock(&global_lock); + return NULL; +} + +static void create_max_threads(void *(*thread_fn)(void *)) +{ + int i, ret; + + for (i = 0; i < MAX_THREADS; i++) { + ret = pthread_create(&threads[i], NULL, thread_fn, NULL); + if (ret) + ksft_exit_fail_msg("pthread_create failed: %m\n"); + } +} + +static void join_max_threads(void) +{ + int i, ret; + + for (i = 0; i < MAX_THREADS; i++) { + ret = pthread_join(threads[i], NULL); + if (ret) + ksft_exit_fail_msg("pthread_join failed for thread %d\n", i); + } +} + +static void usage(char *prog) +{ + printf("Usage: %s\n", prog); + printf(" -c Use color\n"); + printf(" -g Test global hash instead intead local immutable \n"); + printf(" -h Display this help message\n"); + printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n", + VQUIET, VCRITICAL, VINFO); +} + +static const char *test_msg_auto_create = "Automatic hash bucket init on thread creation.\n"; +static const char *test_msg_auto_inc = "Automatic increase with more than 16 CPUs\n"; + +int main(int argc, char *argv[]) +{ + int futex_slots1, futex_slotsn, online_cpus; + pthread_mutexattr_t mutex_attr_pi; + int use_global_hash = 0; + int ret; + char c; + + while ((c = getopt(argc, argv, "cghv:")) != -1) { + switch (c) { + case 'c': + log_color(1); + break; + case 'g': + use_global_hash = 1; + break; + case 'h': + usage(basename(argv[0])); + exit(0); + break; + case 'v': + log_verbosity(atoi(optarg)); + break; + default: + usage(basename(argv[0])); + exit(1); + } + } + + ksft_print_header(); + ksft_set_plan(22); + + ret = pthread_mutexattr_init(&mutex_attr_pi); + ret |= pthread_mutexattr_setprotocol(&mutex_attr_pi, PTHREAD_PRIO_INHERIT); + ret |= pthread_mutex_init(&global_lock, &mutex_attr_pi); + if (ret != 0) { + ksft_exit_fail_msg("Failed to initialize pthread mutex.\n"); + } + /* First thread, expect to be 0, not yet initialized */ + ret = futex_hash_slots_get(); + if (ret != 0) + ksft_exit_fail_msg("futex_hash_slots_get() failed: %d, %m\n", ret); + + ret = futex_hash_immutable_get(); + if (ret != 0) + ksft_exit_fail_msg("futex_hash_immutable_get() failed: %d, %m\n", ret); + + ksft_test_result_pass("Basic get slots and immutable status.\n"); + ret = pthread_create(&threads[0], NULL, thread_return_fn, NULL); + if (ret != 0) + ksft_exit_fail_msg("pthread_create() failed: %d, %m\n", ret); + + ret = pthread_join(threads[0], NULL); + if (ret != 0) + ksft_exit_fail_msg("pthread_join() failed: %d, %m\n", ret); + + /* First thread, has to initialiaze private hash */ + futex_slots1 = futex_hash_slots_get(); + if (futex_slots1 <= 0) { + ksft_print_msg("Current hash buckets: %d\n", futex_slots1); + ksft_exit_fail_msg(test_msg_auto_create); + } + + ksft_test_result_pass(test_msg_auto_create); + + online_cpus = sysconf(_SC_NPROCESSORS_ONLN); + ret = pthread_barrier_init(&barrier_main, NULL, MAX_THREADS + 1); + if (ret != 0) + ksft_exit_fail_msg("pthread_barrier_init failed: %m.\n"); + + ret = pthread_mutex_lock(&global_lock); + if (ret != 0) + ksft_exit_fail_msg("pthread_mutex_lock failed: %m.\n"); + + counter = 0; + create_max_threads(thread_lock_fn); + pthread_barrier_wait(&barrier_main); + + /* + * The current default size of hash buckets is 16. The auto increase + * works only if more than 16 CPUs are available. + */ + ksft_print_msg("Online CPUs: %d\n", online_cpus); + if (online_cpus > 16) { + futex_slotsn = futex_hash_slots_get(); + if (futex_slotsn < 0 || futex_slots1 == futex_slotsn) { + ksft_print_msg("Expected increase of hash buckets but got: %d -> %d\n", + futex_slots1, futex_slotsn); + ksft_exit_fail_msg(test_msg_auto_inc); + } + ksft_test_result_pass(test_msg_auto_inc); + } else { + ksft_test_result_skip(test_msg_auto_inc); + } + ret = pthread_mutex_unlock(&global_lock); + + /* Once the user changes it, it has to be what is set */ + futex_hash_slots_set_verify(2); + futex_hash_slots_set_verify(4); + futex_hash_slots_set_verify(8); + futex_hash_slots_set_verify(32); + futex_hash_slots_set_verify(16); + + ret = futex_hash_slots_set(15, 0); + ksft_test_result(ret < 0, "Use 15 slots\n"); + + futex_hash_slots_set_verify(2); + join_max_threads(); + ksft_test_result(counter == MAX_THREADS, "Created of waited for %d of %d threads\n", + counter, MAX_THREADS); + counter = 0; + /* Once the user set something, auto reisze must be disabled */ + ret = pthread_barrier_init(&barrier_main, NULL, MAX_THREADS); + + create_max_threads(thread_lock_fn); + join_max_threads(); + + ret = futex_hash_slots_get(); + ksft_test_result(ret == 2, "No more auto-resize after manaul setting, got %d\n", + ret); + + futex_hash_slots_set_must_fail(1 << 29, 0); + + /* + * Once the private hash has been made immutable or global hash has been requested, + * then this requested can not be undone. + */ + if (use_global_hash) { + ret = futex_hash_slots_set(0, 0); + ksft_test_result(ret == 0, "Global hash request\n"); + } else { + ret = futex_hash_slots_set(4, FH_FLAG_IMMUTABLE); + ksft_test_result(ret == 0, "Immutable resize to 4\n"); + } + if (ret != 0) + goto out; + + futex_hash_slots_set_must_fail(4, 0); + futex_hash_slots_set_must_fail(4, FH_FLAG_IMMUTABLE); + futex_hash_slots_set_must_fail(8, 0); + futex_hash_slots_set_must_fail(8, FH_FLAG_IMMUTABLE); + futex_hash_slots_set_must_fail(0, FH_FLAG_IMMUTABLE); + futex_hash_slots_set_must_fail(6, FH_FLAG_IMMUTABLE); + + ret = pthread_barrier_init(&barrier_main, NULL, MAX_THREADS); + if (ret != 0) { + ksft_exit_fail_msg("pthread_barrier_init failed: %m\n"); + return 1; + } + create_max_threads(thread_lock_fn); + join_max_threads(); + + ret = futex_hash_slots_get(); + if (use_global_hash) { + ksft_test_result(ret == 0, "Continue to use global hash\n"); + } else { + ksft_test_result(ret == 4, "Continue to use the 4 hash buckets\n"); + } + + ret = futex_hash_immutable_get(); + ksft_test_result(ret == 1, "Hash reports to be immutable\n"); + +out: + ksft_finished(); + return 0; +} diff --git a/tools/testing/selftests/futex/functional/run.sh b/tools/testing/selftests/futex/functional/run.sh index 5ccd599da6c303..81739849f2994d 100755 --- a/tools/testing/selftests/futex/functional/run.sh +++ b/tools/testing/selftests/futex/functional/run.sh @@ -82,3 +82,10 @@ echo echo ./futex_waitv $COLOR + +echo +./futex_priv_hash $COLOR +./futex_priv_hash -g $COLOR + +echo +./futex_numa_mpol $COLOR diff --git a/tools/testing/selftests/futex/include/futex2test.h b/tools/testing/selftests/futex/include/futex2test.h index 9d305520e849bd..ea79662405bc5a 100644 --- a/tools/testing/selftests/futex/include/futex2test.h +++ b/tools/testing/selftests/futex/include/futex2test.h @@ -8,6 +8,53 @@ #define u64_to_ptr(x) ((void *)(uintptr_t)(x)) +#ifndef __NR_futex_waitv +#define __NR_futex_waitv 449 +struct futex_waitv { + __u64 val; + __u64 uaddr; + __u32 flags; + __u32 __reserved; +}; +#endif + +#ifndef __NR_futex_wake +#define __NR_futex_wake 454 +#endif + +#ifndef __NR_futex_wait +#define __NR_futex_wait 455 +#endif + +#ifndef FUTEX2_SIZE_U32 +#define FUTEX2_SIZE_U32 0x02 +#endif + +#ifndef FUTEX2_NUMA +#define FUTEX2_NUMA 0x04 +#endif + +#ifndef FUTEX2_MPOL +#define FUTEX2_MPOL 0x08 +#endif + +#ifndef FUTEX2_PRIVATE +#define FUTEX2_PRIVATE FUTEX_PRIVATE_FLAG +#endif + +#ifndef FUTEX2_NO_NODE +#define FUTEX_NO_NODE (-1) +#endif + +#ifndef FUTEX_32 +#define FUTEX_32 FUTEX2_SIZE_U32 +#endif + +struct futex32_numa { + futex_t futex; + futex_t numa; +}; + /** * futex_waitv - Wait at multiple futexes, wake on any * @waiters: Array of waiters @@ -20,3 +67,26 @@ static inline int futex_waitv(volatile struct futex_waitv *waiters, unsigned lon { return syscall(__NR_futex_waitv, waiters, nr_waiters, flags, timo, clockid); } + +/* + * futex_wait() - block on uaddr with optional timeout + * @val: Expected value + * @flags: FUTEX2 flags + * @timeout: Relative timeout + * @clockid: Clock id for the timeout + */ +static inline int futex2_wait(void *uaddr, long val, unsigned int flags, + struct timespec *timeout, clockid_t clockid) +{ + return syscall(__NR_futex_wait, uaddr, val, ~0U, flags, timeout, clockid); +} + +/* + * futex2_wake() - Wake a number of futexes + * @nr: Number of threads to wake at most + * @flags: FUTEX2 flags + */ +static inline int futex2_wake(void *uaddr, int nr, unsigned int flags) +{ + return syscall(__NR_futex_wake, uaddr, ~0U, nr, flags); +} |