Syzbot reported the following [1]:
BUG: kernel NULL pointer dereference, address: 0000000000000008
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 2d993067 P4D 2d993067 PUD 19a3c067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 3852 Comm: kworker/1:2 Not tainted 5.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events free_ipc
RIP: 0010:kasan_record_aux_stack+0x77/0xb0
Add null checking slab object from kasan_get_alloc_meta()
in order to avoid null pointer dereference.
[1] https://syzkaller.appspot.com/x/log.txt?x=10a82a50d00000
Signed-off-by: Walter Wu <[email protected]>
Suggested-by: Dmitry Vyukov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
CC: Dmitry Vyukov <[email protected]>
CC: Andrey Konovalov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Andrew Morton <[email protected]>
---
mm/kasan/generic.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 1dd5a0f99372..5106b84b07d4 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -337,6 +337,8 @@ void kasan_record_aux_stack(void *addr)
cache = page->slab_cache;
object = nearest_obj(cache, page, addr);
alloc_meta = kasan_get_alloc_meta(cache, object);
+ if (!alloc_meta)
+ return;
alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0];
alloc_meta->aux_stack[0] = kasan_save_stack(GFP_NOWAIT);
--
2.18.0