From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linuxppc-dev@lists.ozlabs.org,
LKML <linux-kernel@vger.kernel.org>,
davidlohr@hp.com, paulus@samba.org, tglx@linutronix.de,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
torvalds@linux-foundation.org, mingo@kernel.org
Subject: Re: Tasks stuck in futex code (in 3.14-rc6)
Date: Thu, 20 Mar 2014 11:03:50 +0530 [thread overview]
Message-ID: <20140320053350.GB30295@linux.vnet.ibm.com> (raw)
In-Reply-To: <20140319170829.GD8557@laptop.programming.kicks-ass.net>
> > Joy,.. let me look at that with ppc in mind.
>
> OK; so while pretty much all the comments from that patch are utter
> nonsense (what was I thinking), I cannot actually find a real bug.
>
> But could you try the below which replaces a control dependency with a
> full barrier. The control flow is plenty convoluted that I think the
> control barrier isn't actually valid anymore and that might indeed
> explain the fail.
>
Unfortunately the patch didnt help. Still seeing tasks stuck
# ps -Ao pid,tt,user,fname,tmout,f,wchan | grep futex
14680 pts/0 root java - 0 futex_wait_queue_me
14797 pts/0 root java - 0 futex_wait_queue_me
# :> /var/log/messages
# echo t > /proc/sysrq-trigger
# grep futex_wait_queue_me /var/log/messages | wc -l
334
#
[ 6904.211478] Call Trace:
[ 6904.211481] [c000000fa1f1b4d0] [0000000000000020] 0x20 (unreliable)
[ 6904.211486] [c000000fa1f1b6a0] [c000000000015208] .__switch_to+0x1e8/0x330
[ 6904.211491] [c000000fa1f1b750] [c000000000702f00] .__schedule+0x360/0x8b0
[ 6904.211495] [c000000fa1f1b9d0] [c000000000147348] .futex_wait_queue_me+0xf8/0x1a0
[ 6904.211500] [c000000fa1f1ba60] [c0000000001486dc] .futex_wait+0x17c/0x2a0
[ 6904.211505] [c000000fa1f1bc10] [c00000000014a614] .do_futex+0x254/0xd80
[ 6904.211510] [c000000fa1f1bd60] [c00000000014b25c] .SyS_futex+0x11c/0x1d0
[ 6904.238874] [c000000fa1f1be30] [c00000000000a0fc] syscall_exit+0x0/0x7c
[ 6904.238879] java S 00003fff825f6044 0 14682 14076 0x00000080
Is there any other information that I provide that can help?
--
Thanks and Regards
Srikar Dronamraju
WARNING: multiple messages have this Message-ID (diff)
From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: davidlohr@hp.com, torvalds@linux-foundation.org,
tglx@linutronix.de, mingo@kernel.org,
LKML <linux-kernel@vger.kernel.org>,
linuxppc-dev@lists.ozlabs.org, benh@kernel.crashing.org,
paulus@samba.org, Paul McKenney <paulmck@linux.vnet.ibm.com>
Subject: Re: Tasks stuck in futex code (in 3.14-rc6)
Date: Thu, 20 Mar 2014 11:03:50 +0530 [thread overview]
Message-ID: <20140320053350.GB30295@linux.vnet.ibm.com> (raw)
In-Reply-To: <20140319170829.GD8557@laptop.programming.kicks-ass.net>
> > Joy,.. let me look at that with ppc in mind.
>
> OK; so while pretty much all the comments from that patch are utter
> nonsense (what was I thinking), I cannot actually find a real bug.
>
> But could you try the below which replaces a control dependency with a
> full barrier. The control flow is plenty convoluted that I think the
> control barrier isn't actually valid anymore and that might indeed
> explain the fail.
>
Unfortunately the patch didnt help. Still seeing tasks stuck
# ps -Ao pid,tt,user,fname,tmout,f,wchan | grep futex
14680 pts/0 root java - 0 futex_wait_queue_me
14797 pts/0 root java - 0 futex_wait_queue_me
# :> /var/log/messages
# echo t > /proc/sysrq-trigger
# grep futex_wait_queue_me /var/log/messages | wc -l
334
#
[ 6904.211478] Call Trace:
[ 6904.211481] [c000000fa1f1b4d0] [0000000000000020] 0x20 (unreliable)
[ 6904.211486] [c000000fa1f1b6a0] [c000000000015208] .__switch_to+0x1e8/0x330
[ 6904.211491] [c000000fa1f1b750] [c000000000702f00] .__schedule+0x360/0x8b0
[ 6904.211495] [c000000fa1f1b9d0] [c000000000147348] .futex_wait_queue_me+0xf8/0x1a0
[ 6904.211500] [c000000fa1f1ba60] [c0000000001486dc] .futex_wait+0x17c/0x2a0
[ 6904.211505] [c000000fa1f1bc10] [c00000000014a614] .do_futex+0x254/0xd80
[ 6904.211510] [c000000fa1f1bd60] [c00000000014b25c] .SyS_futex+0x11c/0x1d0
[ 6904.238874] [c000000fa1f1be30] [c00000000000a0fc] syscall_exit+0x0/0x7c
[ 6904.238879] java S 00003fff825f6044 0 14682 14076 0x00000080
Is there any other information that I provide that can help?
--
Thanks and Regards
Srikar Dronamraju
next prev parent reply other threads:[~2014-03-20 5:34 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-19 15:26 Tasks stuck in futex code (in 3.14-rc6) Srikar Dronamraju
2014-03-19 15:26 ` Srikar Dronamraju
2014-03-19 15:47 ` Peter Zijlstra
2014-03-19 15:47 ` Peter Zijlstra
2014-03-19 16:09 ` Srikar Dronamraju
2014-03-19 16:09 ` Srikar Dronamraju
2014-03-19 17:08 ` Peter Zijlstra
2014-03-19 17:08 ` Peter Zijlstra
2014-03-19 18:06 ` Davidlohr Bueso
2014-03-19 18:06 ` Davidlohr Bueso
2014-03-20 5:33 ` Srikar Dronamraju [this message]
2014-03-20 5:33 ` Srikar Dronamraju
2014-03-20 5:56 ` Davidlohr Bueso
2014-03-20 5:56 ` Davidlohr Bueso
2014-03-20 10:08 ` Srikar Dronamraju
2014-03-20 10:08 ` Srikar Dronamraju
2014-03-20 15:06 ` Davidlohr Bueso
2014-03-20 15:06 ` Davidlohr Bueso
2014-03-20 16:31 ` Davidlohr Bueso
2014-03-20 16:31 ` Davidlohr Bueso
2014-03-20 20:23 ` Benjamin Herrenschmidt
2014-03-20 20:23 ` Benjamin Herrenschmidt
2014-03-20 16:41 ` Linus Torvalds
2014-03-20 16:41 ` Linus Torvalds
2014-03-20 17:18 ` Davidlohr Bueso
2014-03-20 17:18 ` Davidlohr Bueso
2014-03-20 17:42 ` Linus Torvalds
2014-03-20 17:42 ` Linus Torvalds
2014-03-20 18:03 ` Davidlohr Bueso
2014-03-20 18:03 ` Davidlohr Bueso
2014-03-20 18:16 ` Linus Torvalds
2014-03-20 18:16 ` Linus Torvalds
2014-03-20 18:36 ` Linus Torvalds
2014-03-20 18:36 ` Linus Torvalds
2014-03-20 19:08 ` Davidlohr Bueso
2014-03-20 19:08 ` Davidlohr Bueso
2014-03-20 19:25 ` Linus Torvalds
2014-03-20 19:25 ` Linus Torvalds
2014-03-20 20:20 ` Davidlohr Bueso
2014-03-20 20:20 ` Davidlohr Bueso
2014-03-20 20:36 ` Linus Torvalds
2014-03-20 20:36 ` Linus Torvalds
2014-03-21 4:55 ` Srikar Dronamraju
2014-03-21 4:55 ` Srikar Dronamraju
2014-03-21 5:24 ` Linus Torvalds
2014-03-21 5:24 ` Linus Torvalds
2014-03-22 2:27 ` Srikar Dronamraju
2014-03-22 2:27 ` Srikar Dronamraju
2014-03-22 3:36 ` Davidlohr Bueso
2014-03-22 3:36 ` Davidlohr Bueso
2014-03-20 7:23 ` Peter Zijlstra
2014-03-20 7:23 ` Peter Zijlstra
2014-03-19 16:04 ` Linus Torvalds
2014-03-19 16:04 ` Linus Torvalds
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