Re: 3.0.3 oops. memory related?

KAMEZAWA Hiroyuki
2011-09-07T00:21:17Z

On Wed, 7 Sep 2011 08:38:18 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> On Tue, 06 Sep 2011 19:50:09 +0200
> Anders <aeriksson2@gmail.com> wrote:
>
> > On 09/05/11 02:49, KAMEZAWA Hiroyuki wrote:
> > > On Sun, 04 Sep 2011 20:49:42 +0200
> > > Anders <aeriksson2@gmail.com> wrote:
> > >
> > > > I've got kdump setup to collect oopes. I found this in the log. Not sure
> > > > what it's related to.
> > > >
> > >
> > > > <4>[47900.533010] [<ffffffff810ab79f>] ?
> > > > mem_cgroup_count_vm_event+0x15/0x67
> > > > <4>[47900.533010] [<ffffffff810987e5>] ? handle_mm_fault+0x3b/0x1e8
> > > > <4>[47900.533010] [<ffffffff81049bb3>] ? sched_clock_local+0x13/0x76
> > > > <4>[47900.533010] [<ffffffff8101bdb0>] ? do_page_fault+0x31a/0x33f
> > > > <4>[47900.533010] [<ffffffff81022b80>] ? check_preempt_curr+0x36/0x62
> > > > <4>[47900.533010] [<ffffffff8104bb23>] ? ktime_get_ts+0x65/0xa6
> > > > <4>[47900.533010] [<ffffffff810bfd2c>] ?
> > > > poll_select_copy_remaining+0xce/0xed
> > > > <4>[47900.533010] [<ffffffff814c4b4f>] ? page_fault+0x1f/0x30
> > >
> > > I'll check memcg but...not sure what parts in above log are garbage.
> > > At quick glance, mem_cgroup_count_vm_event() does enough NULL check
> > > but faulted address was..
> > >
> > > > <0>[47900.533010] CR2: ffffc5217e257cf0
> > >
> > > This seems not NULL referencing.
> > >
> > > #define VMALLOC_START _AC(0xffffc90000000000, UL)
> > > #define VMALLOC_END _AC(0xffffe8ffffffffff, UL)
> > >
> > > This is not vmalloc area...hmm. could you show your disassemble of
> > > mem_cgroup_count_vm_event() ? and .config ?
> > >
> > How do I disassembe it?
> >
>
> # make mm/memcontrol.o
> # objdump -d memcontrol.o > file
>
> please cut out mem_cgroup_count_vm_event() from dumpped file.
>

Sorry, I made mistake ..the log says

<1>[47900.533010] RIP [<ffffffff81097d18>] handle_pte_fault+0x24/0x70a
<4>[47900.533010] RSP <ffff880024c27db8>
<0>[47900.533010] CR2: ffffc5217e257cf0

<4>[47900.533010] RSP: 0000:ffff880024c27db8 EFLAGS: 00010296
<4>[47900.533010] RAX: 0000000000000cf0 RBX: ffff88006c3b2a68 RCX:
ffffc5217e257cf0
<4>[47900.533010] RDX: 000000000059effe RSI: ffff88006c3b2a68 RDI:
ffff88006d6d2ac0
<4>[47900.533010] RBP: ffffc5217e257cf0 R08: ffff880024d3b010 R09:
0000000000000028
Hm. CR2==RBP...then accessing RBP caused the fault. But it seems this
RBP was accessed in this function before reaching EIP.

your .config says
CONFIG_HAVE_FUNCTION_TRACER=y
CONFIG_HAVE_FUNCTION_GRAPH_TRACER=y
CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST=y
CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST=y
CONFIG_HAVE_DYNAMIC_FTRACE=y
CONFIG_HAVE_FTRACE_MCOUNT_RECORD=y
CONFIG_HAVE_SYSCALL_TRACEPOINTS=y
CONFIG_HAVE_C_RECORDMCOUNT=y

In my binary,

ffffffff8113b820 <handle_pte_fault>:
ffffffff8113b820: 55 push %rbp
ffffffff8113b821: 48 89 e5 mov %rsp,%rbp
ffffffff8113b824: 48 81 ec c0 00 00 00 sub $0xc0,%rsp
ffffffff8113b82b: 48 89 5d d8 mov %rbx,-0x28(%rbp)
ffffffff8113b82f: 4c 89 65 e0 mov %r12,-0x20(%rbp)
ffffffff8113b833: 4c 89 6d e8 mov %r13,-0x18(%rbp)
ffffffff8113b837: 4c 89 75 f0 mov %r14,-0x10(%rbp)
ffffffff8113b83b: 4c 89 7d f8 mov %r15,-0x8(%rbp)
ffffffff8113b83f: e8 fc d4 47 00 callq ffffffff815b8d40 <mcount>
ffffffff8113b844: 4c 89 45 b8 mov %r8,-0x48(%rbp)
ffffffff8113b848: 4c 8b 29 mov (%rcx),%r13

handle_pte_fault + 0x24 is just after mcount. And caused fault by accessing
%rbp...returning from a funciton ?
Hmm...problem with tracing ? I'm sorry if I misunderstand something.
Anyway, CCing ftrace guys for getting information.

Thanks,
-Kame