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| author | Hongfu Li <lihongfu@kylinos.cn> | 2026-05-13 10:52:23 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-05-28 21:31:55 -0700 |
| commit | 1f08743cfd66f0e79bd336ff912d068ebafeedc8 (patch) | |
| tree | 1f863800534923dbce35fed681246e0bbc49a2e1 /tools | |
| parent | ce6133eea67fd206cb034e8e5ffbb4ad687e3f77 (diff) | |
| download | linux-next-history-1f08743cfd66f0e79bd336ff912d068ebafeedc8.tar.gz | |
selftests/mm: fix incorrect mmap() error handling with NULL instead of MAP_FAILED
mmap() returns MAP_FAILED, which is defined as (void *)-1, on error, not
NULL. Several selftests incorrectly check the return value of mmap()
using !ptr or ptr == NULL, which would erroneously treat MAP_FAILED as a
valid pointer since MAP_FAILED is non-zero and non-NULL. This can lead to
segfaults when mmap() actually fails under memory pressure.
Link: https://lore.kernel.org/20260513025223.592766-1-lihongfu@kylinos.cn
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/mm/ksm_tests.c | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/mm/madv_populate.c | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/mm/soft-dirty.c | 4 | ||||
| -rw-r--r-- | tools/testing/selftests/mm/vm_util.c | 2 |
4 files changed, 5 insertions, 5 deletions
diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c index 64d1c63ae8c07..a050f4840cfa3 100644 --- a/tools/testing/selftests/mm/ksm_tests.c +++ b/tools/testing/selftests/mm/ksm_tests.c @@ -174,7 +174,7 @@ static void *allocate_memory(void *ptr, int prot, int mapping, char data, size_ { void *map_ptr = mmap(ptr, map_size, PROT_WRITE, mapping, -1, 0); - if (!map_ptr) { + if (map_ptr == MAP_FAILED) { ksft_perror("mmap"); return NULL; } diff --git a/tools/testing/selftests/mm/madv_populate.c b/tools/testing/selftests/mm/madv_populate.c index 88050e0f829a0..7fce5d0b622be 100644 --- a/tools/testing/selftests/mm/madv_populate.c +++ b/tools/testing/selftests/mm/madv_populate.c @@ -34,7 +34,7 @@ static void sense_support(void) addr = mmap(0, pagesize, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); - if (!addr) + if (addr == MAP_FAILED) ksft_exit_fail_msg("mmap failed\n"); ret = madvise(addr, pagesize, MADV_POPULATE_READ); diff --git a/tools/testing/selftests/mm/soft-dirty.c b/tools/testing/selftests/mm/soft-dirty.c index c426c4636ef57..fb1864a68e1c6 100644 --- a/tools/testing/selftests/mm/soft-dirty.c +++ b/tools/testing/selftests/mm/soft-dirty.c @@ -143,7 +143,7 @@ static void test_mprotect(int pagemap_fd, int pagesize, bool anon) if (anon) { map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); - if (!map) + if (map == MAP_FAILED) ksft_exit_fail_msg("anon mmap failed\n"); } else { test_fd = open(fname, O_RDWR | O_CREAT, 0664); @@ -155,7 +155,7 @@ static void test_mprotect(int pagemap_fd, int pagesize, bool anon) ftruncate(test_fd, pagesize); map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE, MAP_SHARED, test_fd, 0); - if (!map) + if (map == MAP_FAILED) ksft_exit_fail_msg("file mmap failed\n"); } diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 336a26751d3fa..311fc5b4513eb 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -396,7 +396,7 @@ bool softdirty_supported(void) /* New mappings are expected to be marked with VM_SOFTDIRTY (sd). */ addr = mmap(0, pagesize, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); - if (!addr) + if (addr == MAP_FAILED) ksft_exit_fail_msg("mmap failed\n"); supported = check_vmflag(addr, "sd"); |