diff options
| author | Ilya Leoshkevich <iii@linux.ibm.com> | 2024-06-21 13:35:02 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-07-03 19:30:23 -0700 |
| commit | adea98761806642500003b252e095b151c47e807 (patch) | |
| tree | 8d8576e9601762f4a0a4b2fe3e360fa503034f53 /mm/slub.c | |
| parent | 0e9a8550f320db944e4cf036d93c5debf0e574a7 (diff) | |
mm: slub: disable KMSAN when checking the padding bytes
Even though the KMSAN warnings generated by memchr_inv() are suppressed by
metadata_access_enable(), its return value may still be poisoned.
The reason is that the last iteration of memchr_inv() returns `*start !=
value ? start : NULL`, where *start is poisoned. Because of this,
somewhat counterintuitively, the shadow value computed by
visitSelectInst() is equal to `(uintptr_t)start`.
One possibility to fix this, since the intention behind guarding
memchr_inv() behind metadata_access_enable() is to touch poisoned metadata
without triggering KMSAN, is to unpoison its return value. However, this
approach is too fragile. So simply disable the KMSAN checks in the
respective functions.
Link: https://lkml.kernel.org/r/20240621113706.315500-19-iii@linux.ibm.com
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <kasan-dev@googlegroups.com>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/slub.c')
| -rw-r--r-- | mm/slub.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/mm/slub.c b/mm/slub.c index 10e396e1d495..177ad7d3288b 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1176,9 +1176,16 @@ static void restore_bytes(struct kmem_cache *s, char *message, u8 data, memset(from, data, to - from); } -static int check_bytes_and_report(struct kmem_cache *s, struct slab *slab, - u8 *object, char *what, - u8 *start, unsigned int value, unsigned int bytes) +#ifdef CONFIG_KMSAN +#define pad_check_attributes noinline __no_kmsan_checks +#else +#define pad_check_attributes +#endif + +static pad_check_attributes int +check_bytes_and_report(struct kmem_cache *s, struct slab *slab, + u8 *object, char *what, + u8 *start, unsigned int value, unsigned int bytes) { u8 *fault; u8 *end; @@ -1270,7 +1277,8 @@ static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p) } /* Check the pad bytes at the end of a slab page */ -static void slab_pad_check(struct kmem_cache *s, struct slab *slab) +static pad_check_attributes void +slab_pad_check(struct kmem_cache *s, struct slab *slab) { u8 *start; u8 *fault; |