From: Michal Hocko <mhocko@suse.cz>
To: Richard Weinberger <richard@nod.at>
Cc: LKML <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
cgroups mailinglist <cgroups@vger.kernel.org>,
"kamezawa.hiroyu@jp.fujitsu.com" <kamezawa.hiroyu@jp.fujitsu.com>,
bsingharora@gmail.com, hannes@cmpxchg.org
Subject: Re: mem_cgroup_page_lruvec: BUG: unable to handle kernel NULL pointer dereference at 00000000000001a8
Date: Thu, 13 Jun 2013 15:32:44 +0200 [thread overview]
Message-ID: <20130613133244.GD23070@dhcp22.suse.cz> (raw)
In-Reply-To: <20130613132908.GC23070@dhcp22.suse.cz>
Ohh and could you post the config please? Sorry should have asked
earlier.
On Thu 13-06-13 15:29:08, Michal Hocko wrote:
>
> On Thu 13-06-13 14:06:20, Richard Weinberger wrote:
> [...]
> > All code
> > ========
> > 0: 89 50 08 mov %edx,0x8(%rax)
> > 3: 48 89 d1 mov %rdx,%rcx
> > 6: 0f 1f 40 00 nopl 0x0(%rax)
> > a: 49 8b 04 24 mov (%r12),%rax
> > e: 48 89 c2 mov %rax,%rdx
> > 11: 48 c1 e8 38 shr $0x38,%rax
> > 15: 83 e0 03 and $0x3,%eax
> nid = page_to_nid
> > 18: 48 c1 ea 3a shr $0x3a,%rdx
> zid = page_zonenum
>
> > 1c: 48 69 c0 38 01 00 00 imul $0x138,%rax,%rax
> > 23: 48 03 84 d1 e0 02 00 add 0x2e0(%rcx,%rdx,8),%rax
> &memcg->nodeinfo[nid]->zoneinfo[zid]
>
> > 2a: 00
> > 2b:* 48 3b 58 70 cmp 0x70(%rax),%rbx <-- trapping instruction
>
> OK, so this maps to:
> if (unlikely(lruvec->zone != zone)) <<<
> lruvec->zone = zone;
>
> > [35355.883056] RSP: 0000:ffff88003d523aa8 EFLAGS: 00010002
> > [35355.883056] RAX: 0000000000000138 RBX: ffff88003fffa600 RCX: ffff88003e04a800
> > [35355.883056] RDX: 0000000000000020 RSI: 0000000000000000 RDI: 0000000000028500
> > [35355.883056] RBP: ffff88003d523ab8 R08: 0000000000000000 R09: 0000000000000000
> > [35355.883056] R10: 0000000000000000 R11: dead000000100100 R12: ffffea0000a14000
> > [35355.883056] R13: ffff88003e04b138 R14: ffff88003d523bb8 R15: ffffea0000a14020
> > [35355.883056] FS: 0000000000000000(0000) GS:ffff88003fd80000(0000)
>
> RAX (lruvec) is obviously incorrect and it doesn't make any sense. rax should
> contain an address at an offset from ffff88003e04a800 But there is 0x138 there
> instead.
>
> Is this easily reproducible? Could you configure kdump.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2013-06-13 13:32 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-13 11:48 mem_cgroup_page_lruvec: BUG: unable to handle kernel NULL pointer dereference at 00000000000001a8 richard -rw- weinberger
2013-06-13 12:02 ` Michal Hocko
2013-06-13 12:06 ` Richard Weinberger
2013-06-13 13:29 ` Michal Hocko
2013-06-13 13:32 ` Michal Hocko [this message]
2013-06-13 13:34 ` Richard Weinberger
2013-06-13 14:39 ` Michal Hocko
2013-06-13 14:45 ` Richard Weinberger
2013-06-13 14:57 ` Richard Weinberger
2013-06-13 15:19 ` Michal Hocko
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