št 13. 5. 2021 o 6:44 Andrew Morton akpm@linux-foundation.org napísal(a):
On Tue, 11 May 2021 17:07:33 +0200 glittao@gmail.com wrote:
From: Oliver Glitta glittao@gmail.com
SLUB has resiliency_test() function which is hidden behind #ifdef SLUB_RESILIENCY_TEST that is not part of Kconfig, so nobody runs it. KUnit should be a proper replacement for it.
Try changing byte in redzone after allocation and changing pointer to next free node, first byte, 50th byte and redzone byte. Check if validation finds errors.
There are several differences from the original resiliency test: Tests create own caches with known state instead of corrupting shared kmalloc caches.
The corruption of freepointer uses correct offset, the original resiliency test got broken with freepointer changes.
Scratch changing random byte test, because it does not have meaning in this form where we need deterministic results.
Add new option CONFIG_SLUB_KUNIT_TEST in Kconfig. Tests next_pointer, first_word and clobber_50th_byte do not run with KASAN option on. Because the test deliberately modifies non-allocated objects.
Use kunit_resource to count errors in cache and silence bug reports. Count error whenever slab_bug() or slab_fix() is called or when the count of pages is wrong.
...
lib/slub_kunit.c | 155 ++++++++++++++++++++++++++++++++++++++++++++++ mm/slab.h | 1 + mm/slub.c | 46 +++++++++++++- 5 files changed, 212 insertions(+), 3 deletions(-) create mode 100644 lib/slub_kunit.c
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 678c13967580..7723f58a9394 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2429,6 +2429,18 @@ config BITS_TEST
If unsure, say N.+config SLUB_KUNIT_TEST
tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTSThis means it can be compiled as a kernel module. Did you runtime test the code as a module?
We tested this as a module in the previous version, but I forgot to try it with this new one. So we didn't find this error. Thank you for your fix.
ERROR: modpost: "kasan_enable_current" [lib/slub_kunit.ko] undefined! ERROR: modpost: "kasan_disable_current" [lib/slub_kunit.ko] undefined!
--- a/mm/kasan/common.c~a +++ a/mm/kasan/common.c @@ -51,11 +51,14 @@ void kasan_enable_current(void) { current->kasan_depth++; } +EXPORT_SYMBOL(kasan_enable_current);
void kasan_disable_current(void) { current->kasan_depth--; } +EXPORT_SYMBOL(kasan_disable_current);
#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
void __kasan_unpoison_range(const void *address, size_t size) _