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| author | Maninder Singh <maninder1.s@samsung.com> | 2021-03-16 16:07:10 +0530 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-05-10 16:01:41 -0700 |
| commit | 0cbc124bce8c527eb14c87f634683c5bcf4299c7 (patch) | |
| tree | cd8254c3e19914f6feed24668f0fe2bfddd28cd7 /mm/slub.c | |
| parent | 6efb943b8616ec53a5e444193dccf1af9ad627b5 (diff) | |
| download | lwn-0cbc124bce8c527eb14c87f634683c5bcf4299c7.tar.gz lwn-0cbc124bce8c527eb14c87f634683c5bcf4299c7.zip | |
mm/slub: Fix backtrace of objects to handle redzone adjustment
This commit fixes commit 8e7f37f2aaa5 ("mm: Add mem_dump_obj() to print
source of memory block").
With current code, the backtrace of allocated object is incorrect:
/ # cat /proc/meminfo
[ 14.969843] slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 0 size 64 allocated at 0x6b6b6b6b
[ 14.970635] 0x6b6b6b6b
[ 14.970794] 0x6b6b6b6b
[ 14.970932] 0x6b6b6b6b
[ 14.971077] 0x6b6b6b6b
[ 14.971202] 0x6b6b6b6b
[ 14.971317] 0x6b6b6b6b
[ 14.971423] 0x6b6b6b6b
[ 14.971635] 0x6b6b6b6b
[ 14.971740] 0x6b6b6b6b
[ 14.971871] 0x6b6b6b6b
[ 14.972229] 0x6b6b6b6b
[ 14.972363] 0x6b6b6b6b
[ 14.972505] 0xa56b6b6b
[ 14.972631] 0xbbbbbbbb
[ 14.972734] 0xc8ab0400
[ 14.972891] meminfo_proc_show+0x40/0x4fc
The reason is that the object address was not adjusted for the red zone.
With this fix, the backtrace is correct:
/ # cat /proc/meminfo
[ 14.870782] slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 128 size 64 allocated at meminfo_proc_show+0x40/0x4f4
[ 14.871817] meminfo_proc_show+0x40/0x4f4
[ 14.872035] seq_read_iter+0x18c/0x4c4
[ 14.872229] proc_reg_read_iter+0x84/0xac
[ 14.872433] generic_file_splice_read+0xe8/0x17c
[ 14.872621] splice_direct_to_actor+0xb8/0x290
[ 14.872747] do_splice_direct+0xa0/0xe0
[ 14.872896] do_sendfile+0x2d0/0x438
[ 14.873044] sys_sendfile64+0x12c/0x140
[ 14.873229] ret_fast_syscall+0x0/0x58
[ 14.873372] 0xbe861de4
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'mm/slub.c')
| -rw-r--r-- | mm/slub.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/slub.c b/mm/slub.c index feda53ae62ba..8f2d13508ec9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -4002,6 +4002,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page) !(s->flags & SLAB_STORE_USER)) return; #ifdef CONFIG_SLUB_DEBUG + objp = fixup_red_left(s, objp); trackp = get_track(s, objp, TRACK_ALLOC); kpp->kp_ret = (void *)trackp->addr; #ifdef CONFIG_STACKTRACE |