Re: 2.6.21-rc5-mm1

[Andrew Morton]

On Wed, 28 Mar 2007 18:44:57 +0200
Mariusz Koz__owski <m.kozlowski@xxxxxxxxxx> wrote:

> Hello,
> 
> 	I run 2.6.21-rc4-mm1 with no hangs for a week.
> Then when 2.6.21-rc5-mm1 showed up so I switched to it. Unfortunately
> today my laptop hunged twice in a similar way as described here:
> 
> http://www.ussg.iu.edu/hypermail/linux/kernel/0703.0/index.html#1165

It's not good that we went backwards between those two releases.

> 
> The difference is that it happened when I closed the lid in my laptop.
> When reopend it the box was frozen (ACPI?). Again disk I/O was dead
> so nothing was found in syslog.

Adrian, does this look like any of the bugs whcih you're monitoring?

> I tried to reproduce it and capture something with netconsole.
> I tortured the box for a few hours but the system did not hang. I pushed
> the box real hard and what I got was only oom-killer firing etc ;-)
> Anyway I found something else you might be interested in:
> 
> 
> 
> 1) This happened when 'echo 3 > /proc/sys/vm/drop_caches' on really
>    busy system.
> 
>  =======================================================
>  [ INFO: possible circular locking dependency detected ]
>  2.6.21-rc5-mm1 #1
>  -------------------------------------------------------
>  bash/20633 is trying to acquire lock:
>   (&journal->j_list_lock){--..}, at: [<c01bb60e>] journal_try_to_free_buffers+0x151/0x1bc
>  
>  but task is already holding lock:
>   (inode_lock){--..}, at: [<c0187d46>] drop_pagecache+0x58/0xf9

Yeah, that's a lock ranking error in the drop_caches code.  I have a
super-long-term plan to fix it, but in the short term nothing suggests
itself apart from removing the drop_caches code, I'm afraid.

> 
> 2) This was found a couple minutes later when the system was
>    really busy and close to oom condition.
> 
>  INFO: lockdep is turned off.
>  BUG: soft lockup detected on CPU#0!
>   [<c0104614>] show_trace_log_lvl+0x1a/0x30
>   [<c01052c9>] show_trace+0x12/0x14
>   [<c0105355>] dump_stack+0x16/0x18
>   [<c01467a0>] softlockup_tick+0x81/0xa8
>   [<c011e4dc>] run_local_timers+0x12/0x14
>   [<c011e8dd>] update_process_times+0x2b/0x63
>   [<c012e4be>] tick_sched_timer+0x4d/0x9e
>   [<c012af00>] hrtimer_interrupt+0x12e/0x1a6
>   [<c0106f56>] timer_interrupt+0xe/0x15
>   [<c0146af3>] handle_IRQ_event+0x28/0x59
>   [<c01480a7>] handle_level_irq+0x6e/0xe7
>   [<c0105d3e>] do_IRQ+0x3d/0x7f
>   [<c01041b2>] common_interrupt+0x2e/0x34
>   [<c011afef>] do_softirq+0x4d/0x50
>   [<c011b263>] irq_exit+0x7e/0x80
>   [<c0105d43>] do_IRQ+0x42/0x7f
>   [<c01041b2>] common_interrupt+0x2e/0x34
>   [<c0178bf2>] core_sys_select+0x1c6/0x310
>   [<c0179101>] sys_select+0x39/0x18f
>   [<c0103f44>] sysenter_past_esp+0x5d/0x99
>   =======================
>  Clocksource tsc unstable (delta = 9372804176 ns)
>  Time: acpi_pm clocksource has been installed.
> 
> Please find .config attached. Not sure who to CC on this (as usual ;-)).
> 

I do ;)
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