From: Maninder Singh <maninder1.s@samsung.com>
To: paulmck@kernel.org, linux@armlinux.org.uk, cl@linux.com,
penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com,
akpm@linux-foundation.org, vbabka@suse.cz, 0x7f454c46@gmail.com,
viro@zeniv.linux.org.uk
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
a.sahrawat@samsung.com, Maninder Singh <maninder1.s@samsung.com>,
Vaneet Narang <v.narang@samsung.com>
Subject: [PATCH 1/3] mm/slub: fixing backtrace of objects because of redzone adjustment
Date: Tue, 16 Mar 2021 16:07:10 +0530 [thread overview]
Message-ID: <1615891032-29160-1-git-send-email-maninder1.s@samsung.com> (raw)
In-Reply-To: CGME20210316103723epcas5p1f750d5cfe029fa69aea8d88f0bd408f3@epcas5p1.samsung.com
fixing commit 8e7f37f2aaa5 ("mm: Add mem_dump_obj() to print source
of memory block")
with current code, Backtrace of allocated object is coming wrong:
/ # 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
And reason is red zone was not adjusted from object address.
after adding fixup for redzone, backtrace is coming 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
Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
---
mm/slub.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/slub.c b/mm/slub.c
index 1912c4614248..9d13f0117ae6 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4052,6 +4052,7 @@ 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
--
2.17.1
next parent reply other threads:[~2021-03-16 10:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210316103723epcas5p1f750d5cfe029fa69aea8d88f0bd408f3@epcas5p1.samsung.com>
2021-03-16 10:37 ` Maninder Singh [this message]
[not found] ` <CGME20210316103736epcas5p3758de57b57c732074acc0989e563cc2e@epcas5p3.samsung.com>
2021-03-16 10:37 ` [PATCH 2/3] mm/slub: Add Support for free path information of an object Maninder Singh
2021-03-18 12:35 ` Vlastimil Babka
2021-03-19 23:23 ` Paul E. McKenney
[not found] ` <CGME20210316103745epcas5p3994f29958b7f14aec8cbd90fa518761f@epcas5p3.samsung.com>
2021-03-16 10:37 ` [PATCH 3/3] arm: print alloc free paths for address in registers Maninder Singh
2021-03-16 17:44 ` [PATCH 1/3] mm/slub: fixing backtrace of objects because of redzone adjustment Paul E. McKenney
2021-03-18 12:33 ` Vlastimil Babka
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