selftests/bpf: use ASSERT_STRNEQ to factor in long slab cache names #10324
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subtest_kmem_cache_iter_check_slabinfo() fundamentally compares slab cache names parsed out from /proc/slabinfo against those stored within struct kmem_cache_result. The current problem is that the slab cache name within struct kmem_cache_result is stored within a bounded fixed-length array (sized to SLAB_NAME_MAX(32)), whereas the name parsed out from /proc/slabinfo is not. Meaning, using ASSERT_STREQ() can certainly lead to test failures, particularly when dealing with slab cache names that are longer than SLAB_NAME_MAX(32) bytes. Notably, kmem_cache_create() allows callers to create slab caches with somewhat arbitrarily sized names via its __name identifier argument, so exceeding the SLAB_NAME_MAX(32) limit that is in place now can certainly happen. Make subtest_kmem_cache_iter_check_slabinfo() more reliable by only checking up to sizeof(struct kmem_cache_result.name) - 1 using ASSERT_STRNEQ(). Fixes: a496d0c ("selftests/bpf: Add a test for kmem_cache_iter") Signed-off-by: Matt Bobrowski <[email protected]>
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subtest_kmem_cache_iter_check_slabinfo() fundamentally compares slab
cache names parsed out from /proc/slabinfo against those stored within
struct kmem_cache_result. The current problem is that the slab cache
name within struct kmem_cache_result is stored within a bounded
fixed-length array (sized to SLAB_NAME_MAX(32)), whereas the name
parsed out from /proc/slabinfo is not. Meaning, using ASSERT_STREQ()
can certainly lead to test failures, particularly when dealing with
slab cache names that are longer than SLAB_NAME_MAX(32)
bytes. Notably, kmem_cache_create() allows callers to create slab
caches with somewhat arbitrarily sized names via its __name identifier
argument, so exceeding the SLAB_NAME_MAX(32) limit that is in place
now can certainly happen.
Make subtest_kmem_cache_iter_check_slabinfo() more reliable by only
checking up to sizeof(struct kmem_cache_result.name) - 1 using
ASSERT_STRNEQ().