6.8-stable review patch. If anyone has any objections, please let me know.
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From: Guenter Roeck linux@roeck-us.net
[ Upstream commit b1080c667b3b2c8c38a7fa83ca5567124887abae ]
Two failure patterns are seen randomly when running slub_kunit tests with CONFIG_SLAB_FREELIST_RANDOM and CONFIG_SLAB_FREELIST_HARDENED enabled.
Pattern 1: # test_clobber_zone: pass:1 fail:0 skip:0 total:1 ok 1 test_clobber_zone # test_next_pointer: EXPECTATION FAILED at lib/slub_kunit.c:72 Expected 3 == slab_errors, but slab_errors == 0 (0x0) # test_next_pointer: EXPECTATION FAILED at lib/slub_kunit.c:84 Expected 2 == slab_errors, but slab_errors == 0 (0x0) # test_next_pointer: pass:0 fail:1 skip:0 total:1 not ok 2 test_next_pointer
In this case, test_next_pointer() overwrites p[s->offset], but the data at p[s->offset] is already 0x12.
Pattern 2: ok 1 test_clobber_zone # test_next_pointer: EXPECTATION FAILED at lib/slub_kunit.c:72 Expected 3 == slab_errors, but slab_errors == 2 (0x2) # test_next_pointer: pass:0 fail:1 skip:0 total:1 not ok 2 test_next_pointer
In this case, p[s->offset] has a value other than 0x12, but one of the expected failures is nevertheless missing.
Invert data instead of writing a fixed value to corrupt the cache data structures to fix the problem.
Fixes: 1f9f78b1b376 ("mm/slub, kunit: add a KUnit test for SLUB debugging functionality") Cc: Oliver Glitta glittao@gmail.com Cc: Vlastimil Babka vbabka@suse.cz CC: Daniel Latypov dlatypov@google.com Cc: Marco Elver elver@google.com Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Vlastimil Babka vbabka@suse.cz Signed-off-by: Sasha Levin sashal@kernel.org --- lib/slub_kunit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/slub_kunit.c b/lib/slub_kunit.c index d4a3730b08fa7..4ce9604388069 100644 --- a/lib/slub_kunit.c +++ b/lib/slub_kunit.c @@ -55,7 +55,7 @@ static void test_next_pointer(struct kunit *test)
ptr_addr = (unsigned long *)(p + s->offset); tmp = *ptr_addr; - p[s->offset] = 0x12; + p[s->offset] = ~p[s->offset];
/* * Expecting three errors.