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>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the reStructuredText markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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