Re: 2.6.22.6 + oprofile oops

[Sami Farin <safari-kernel@safari.iki.fi>]

On Sat, Sep 22, 2007 at 14:23:35 +0300, Sami Farin wrote:
> x86_64 SMP kernel v2.6.22.6 (not using callgraph).
> sometimes oprofile works for a longer time... but not this time.
> 
> 2007-09-22 13:53:32.527237777 <1>[ 3372.390188] Unable to handle kernel NULL pointer dereference at 0000000000000650 RIP: 
> 2007-09-22 13:53:32.527245948 <1>[ 3372.390195]  [<ffffffff80652f44>] _spin_lock+0x4/0x20
> 2007-09-22 13:53:32.527247694 <4>[ 3372.390211] PGD 13a6c067 PUD 3ad91067 PMD 0 
> 2007-09-22 13:53:32.527249371 <0>[ 3372.390216] Oops: 0002 [1] SMP 
> 2007-09-22 13:53:32.527250837 <4>[ 3372.390220] CPU 0 
> 2007-09-22 13:53:32.527252304 <4>[ 3372.390227] <snip>
...
> 2007-09-22 13:53:32.527385634 <4>[ 3372.390442] Call Trace:
> 2007-09-22 13:53:32.527390314 <4>[ 3372.390457]  [<ffffffff80232b88>] get_task_mm+0x18/0x60
> 2007-09-22 13:53:32.527391990 <4>[ 3372.390484]  [<ffffffff8831abd4>] :oprofile:sync_buffer+0xf4/0x480
> 2007-09-22 13:53:32.527393666 <4>[ 3372.390544]  [<ffffffff8831a6b0>] :oprofile:wq_sync_buffer+0x0/0x60
> 2007-09-22 13:53:32.527399673 <4>[ 3372.390576]  [<ffffffff8831a6e3>] :oprofile:wq_sync_buffer+0x33/0x60
> 2007-09-22 13:53:32.527401419 <4>[ 3372.390602]  [<ffffffff80244bfd>] run_workqueue+0xcd/0x170
> 2007-09-22 13:53:32.527406238 <4>[ 3372.390635]  [<ffffffff802456b3>] worker_thread+0xb3/0x120
> 2007-09-22 13:53:32.527421324 <4>[ 3372.390652]  [<ffffffff80249000>] autoremove_wake_function+0x0/0x40
> 2007-09-22 13:53:32.527423140 <4>[ 3372.390684]  [<ffffffff80245600>] worker_thread+0x0/0x120
> 2007-09-22 13:53:32.527424816 <4>[ 3372.390697]  [<ffffffff80248bfd>] kthread+0x4d/0x80
> 2007-09-22 13:53:32.527426423 <4>[ 3372.390730]  [<ffffffff8020abc8>] child_rip+0xa/0x12
> 2007-09-22 13:53:32.527428099 <4>[ 3372.390810]  [<ffffffff80248bb0>] kthread+0x0/0x80
> 2007-09-22 13:53:32.527444931 <4>[ 3372.390822]  [<ffffffff8020abbe>] child_rip+0x0/0x12

This is easy to trigger with "ping -f 127.0.0.1" (as root).
Oopses inside 0.1s.  If you can't reproduce, try more events and/or smaller
sample count.

May I suggest something: if system is too slow to process events,
find out which event is triggering too often, double the sample count
for it, reset all counters, and log an informative kernel message.
If that's why it's crashing...   if it's some other reason, tough luck
:)

> 2007-09-22 13:53:32.527446817 <4>[ 3372.390844] 
> 2007-09-22 13:53:32.527448144 <4>[ 3372.390846] 
> 2007-09-22 13:53:32.527449541 <4>[ 3372.390846] Code: f0 ff 0f 79 09 f3 90 83 3f 00 7e f9 eb f2 c9 c3 66 66 66 2e 
> 2007-09-22 13:53:32.527455757 <1>[ 3372.390866] RIP  [<ffffffff80652f44>] _spin_lock+0x4/0x20
> 2007-09-22 13:53:32.527457433 <4>[ 3372.390876]  RSP <ffff81003e5fddc0>
> 2007-09-22 13:53:32.527463090 <0>[ 3372.390878] CR2: 0000000000000650
> 
> BTW. does somebody have callgraph working on x86_64 with oprofile?
> I get instant freeze and I need to power cycle system... (callgraph worked on IA-32)

-- 
Do what you love because life is too short for anything else.

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