diff options
| author | Qing Ming <a0yami@mailbox.org> | 2026-05-16 15:08:49 +0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-05-18 09:31:52 -1000 |
| commit | 8817005efbdfdf5d4e4814cb5dc52b53d12917d7 (patch) | |
| tree | 0be542a0dde49a8b72477bcbded6f032be25add6 /mm | |
| parent | 345f40166694e60db6d5cf02233814bb27ac5dec (diff) | |
| download | linux-next-history-8817005efbdfdf5d4e4814cb5dc52b53d12917d7.tar.gz | |
cgroup/rstat: validate cpu before css_rstat_cpu() access
css_rstat_updated() is exposed as a BPF kfunc and accepts a
caller-provided cpu argument. The function uses cpu for per-cpu rstat
lookups without checking whether it refers to a valid possible CPU.
A BPF iter/cgroup program with CAP_BPF and CAP_PERFMON can pass an
invalid cpu value. On an unfixed UBSCAN_BOUNDS test kernel, cpu ==
0x7fffffff triggers:
UBSAN: array-index-out-of-bounds in kernel/cgroup/rstat.c:31:9
index 2147483647 is out of range for type 'long unsigned int [64]'
Call Trace:
css_rstat_updated
bpf_iter_run_prog
cgroup_iter_seq_show
bpf_seq_read
Add cpu validation to the BPF-facing css_rstat_updated() kfunc and
move the common implementation to __css_rstat_updated() for in-kernel
callers.
Fixes: a319185be9f5 ("cgroup: bpf: enable bpf programs to integrate with rstat")
Signed-off-by: Qing Ming <a0yami@mailbox.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memcontrol.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 051b82ebf371c..c7e60f26013c1 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -579,7 +579,7 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val, if (!val) return; - css_rstat_updated(&memcg->css, cpu); + __css_rstat_updated(&memcg->css, cpu); statc_pcpu = memcg->vmstats_percpu; for (; statc_pcpu; statc_pcpu = statc->parent_pcpu) { statc = this_cpu_ptr(statc_pcpu); @@ -2608,7 +2608,7 @@ static inline void account_slab_nmi_safe(struct mem_cgroup *memcg, struct mem_cgroup_per_node *pn = memcg->nodeinfo[pgdat->node_id]; /* preemption is disabled in_nmi(). */ - css_rstat_updated(&memcg->css, smp_processor_id()); + __css_rstat_updated(&memcg->css, smp_processor_id()); if (idx == NR_SLAB_RECLAIMABLE_B) atomic_add(nr, &pn->slab_reclaimable); else @@ -2832,7 +2832,7 @@ static inline void account_kmem_nmi_safe(struct mem_cgroup *memcg, int val) mod_memcg_state(memcg, MEMCG_KMEM, val); } else { /* preemption is disabled in_nmi(). */ - css_rstat_updated(&memcg->css, smp_processor_id()); + __css_rstat_updated(&memcg->css, smp_processor_id()); atomic_add(val, &memcg->kmem_stat); } } |