From: Luca Tettamanti <kronos.it@gmail.com>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, Julia Lawall <julia@diku.dk>,
Manfred Spraul <manfred@colorfullife.com>
Subject: Re: 2.6.35-rc3 deadlocks on semaphore operations
Date: Mon, 21 Jun 2010 22:01:18 +0200 [thread overview]
Message-ID: <20100621200118.GA4021@nb-core2.darkstar.lan> (raw)
In-Reply-To: <alpine.DEB.2.00.1006180940140.11575@router.home>
On Fri, Jun 18, 2010 at 09:49:44AM -0500, Christoph Lameter wrote:
> Can produce it with make-kpkg building a kernel.
[...]
> linux-2.6$ strace -p21561
> Process 21561 attached - interrupt to quit
> semop(32768, {{0, -1, SEM_UNDO}}, 1
>
> linux-2.6$ strace -p21751
> Process 21751 attached - interrupt to quit
> semop(32768, {{0, -1, SEM_UNDO}}, 1
>
> linux-2.6$ strace -p21792
> Process 21792 attached - interrupt to quit
> semop(32768, {{0, -1, SEM_UNDO}}, 1
>
> linux-2.6$ strace -p21793
> Process 21793 attached - interrupt to quit
> semop(32768, {{0, -1, SEM_UNDO}}, 1
Ah! I was trying to understand what was going on with apache... I see
the same symptoms with apache and prefork module: each child serves one
request and then just hangs until it's recycled.
Strace shows the same semop syscall.
# ipcs
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
------ Semaphore Arrays --------
key semid owner perms nsems
0x00000000 65536 www-data 600 1
------ Message Queues --------
key msqid owner perms used-bytes messages
# cat /proc/sysvipc/sem
key semid perms nsems uid gid cuid cgid otime ctime
0 65536 600 1 33 33 0 0 1277149940 1277149903
# /tmp/getall 65536 -v
getall <id> [-v]
found 1 semaphores.
0: 0 (cnt 4 zcnt 0)
Luca
next prev parent reply other threads:[~2010-06-21 20:09 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-18 14:49 2.6.35-rc3 deadlocks on semaphore operations Christoph Lameter
2010-06-18 14:56 ` Christoph Lameter
2010-06-19 14:43 ` Manfred Spraul
2010-06-21 14:31 ` Christoph Lameter
2010-06-21 16:52 ` Manfred Spraul
2010-06-21 17:13 ` Christoph Lameter
2010-06-18 15:34 ` Julia Lawall
2010-06-19 11:06 ` Manfred Spraul
2010-06-21 17:05 ` Christoph Lameter
2010-06-21 17:16 ` Christoph Lameter
2010-06-21 18:05 ` 2.6.35-rc3 deadlocks on wakeup(?) (was on semaphore operations) Christoph Lameter
2010-06-20 6:55 ` 2.6.35-rc3 deadlocks on semaphore operations Maciej Rutecki
2010-06-21 20:01 ` Luca Tettamanti [this message]
2010-06-23 16:29 ` Manfred Spraul
2010-06-23 19:14 ` Luca Tettamanti
2010-06-24 19:22 ` Luca Tettamanti
2010-06-25 21:09 ` Manfred Spraul
2010-06-26 12:52 ` Luca Tettamanti
2010-06-26 15:47 ` 2.6.35-rc3: System unresponsive under load Manfred Spraul
2010-06-26 15:49 ` Manfred Spraul
2010-06-26 16:47 ` Luca Tettamanti
2010-06-30 19:07 ` Manfred Spraul
2010-07-06 16:01 ` Luca Tettamanti
2010-07-07 19:34 ` Luca Tettamanti
2010-07-02 15:53 ` 2.6.35-rc3 deadlocks on semaphore operations Manfred Spraul
2010-06-23 20:27 ` Christoph Lameter
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