From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754780AbbAFKhf (ORCPT ); Tue, 6 Jan 2015 05:37:35 -0500 Received: from cantor2.suse.de ([195.135.220.15]:36815 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753313AbbAFKhc (ORCPT ); Tue, 6 Jan 2015 05:37:32 -0500 Date: Tue, 06 Jan 2015 11:37:31 +0100 Message-ID: From: Takashi Iwai To: sedat.dilek@gmail.com Cc: Dave Jones , Linus Torvalds , LKML , "Peter Zijlstra (Intel)" Subject: Re: Linux 3.19-rc3 In-Reply-To: References:

User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/24.4 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org At Tue, 6 Jan 2015 11:31:34 +0100, Sedat Dilek wrote: > > On Tue, Jan 6, 2015 at 11:28 AM, Takashi Iwai wrote: > > At Tue, 6 Jan 2015 11:06:45 +0100, > > Sedat Dilek wrote: > >> > >> On Tue, Jan 6, 2015 at 10:56 AM, Takashi Iwai wrote: > >> > At Tue, 6 Jan 2015 10:34:30 +0100, > >> > Sedat Dilek wrote: > >> >> > >> >> On Tue, Jan 6, 2015 at 5:49 AM, Sedat Dilek wrote: > >> >> > [ Please CC me I am not subscribed to LKML ] > >> >> > > >> >> > [ QUOTE ] > >> >> > > >> >> > On Mon, Jan 05, 2015 at 05:46:15PM -0800, Linus Torvalds wrote: > >> >> > > It's a day delayed - not because of any particular development issues, > >> >> > > but simply because I was tiling a bathroom yesterday. But rc3 is out > >> >> > > there now, and things have stayed reasonably calm. I really hope that > >> >> > > implies that 3.19 is looking good, but it's equally likely that it's > >> >> > > just that people are still recovering from the holiday season. > >> >> > > > >> >> > > A bit over three quarters of the changes here are drivers - mostly > >> >> > > networking, thermal, input layer, sound, power management. The rest is > >> >> > > misc - filesystems, core networking, some arch fixes, etc. But all of > >> >> > > it is pretty small. > >> >> > > > >> >> > > So go out and test, > >> >> > > >> >> > This has been there since just before rc1. Is there a fix for this > >> >> > stalled in someones git tree maybe ? > >> >> > > >> >> > [ 7.952588] WARNING: CPU: 0 PID: 299 at kernel/sched/core.c:7303 > >> >> > __might_sleep+0x8d/0xa0() > >> >> > [ 7.952592] do not call blocking ops when !TASK_RUNNING; state=1 > >> >> > set at [] prepare_to_wait+0x2a/0x90 > >> >> > [ 7.952595] CPU: 0 PID: 299 Comm: systemd-readahe Not tainted > >> >> > 3.19.0-rc3+ #100 > >> >> > [ 7.952597] 0000000000001c87 00000000720a2c76 ffff8800b2513c88 > >> >> > ffffffff915b47c7 > >> >> > [ 7.952598] ffffffff910a3648 ffff8800b2513ce0 ffff8800b2513cc8 > >> >> > ffffffff91062c30 > >> >> > [ 7.952599] 0000000000000000 ffffffff91796fb2 000000000000026d > >> >> > 0000000000000000 > >> >> > [ 7.952600] Call Trace: > >> >> > [ 7.952603] [] dump_stack+0x4c/0x65 > >> >> > [ 7.952604] [] ? down_trylock+0x28/0x40 > >> >> > [ 7.952606] [] warn_slowpath_common+0x80/0xc0 > >> >> > [ 7.952607] [] warn_slowpath_fmt+0x50/0x70 > >> >> > [ 7.952608] [] ? prepare_to_wait+0x2a/0x90 > >> >> > [ 7.952610] [] ? prepare_to_wait+0x2a/0x90 > >> >> > [ 7.952611] [] __might_sleep+0x8d/0xa0 > >> >> > [ 7.952614] [] mutex_lock_nested+0x39/0x3e0 > >> >> > [ 7.952616] [] ? trace_hardirqs_on+0xd/0x10 > >> >> > [ 7.952617] [] ? prepare_to_wait+0x5c/0x90 > >> >> > [ 7.952620] [] fanotify_read+0xe0/0x5b0 > >> >> > [ 7.952622] [] ? sched_clock_cpu+0xc1/0xd0 > >> >> > [ 7.952624] [] ? selinux_file_permission+0xb9/0x130 > >> >> > [ 7.952626] [] ? prepare_to_wait_event+0xf0/0xf0 > >> >> > [ 7.952628] [] __vfs_read+0x13/0x50 > >> >> > [ 7.952629] [] vfs_read+0x88/0x140 > >> >> > [ 7.952631] [] SyS_read+0x57/0xd0 > >> >> > [ 7.952633] [] system_call_fastpath+0x12/0x17 > >> >> > > >> >> > [ /QUOTE ] > >> >> > > >> >> > I am seeing a similiar call-trace/warning. > >> >> > It is reproducible when running fio (latest: v2.2.4) while my loop-mq > >> >> > tests (see block.git#for-next) > >> >> > > >> >> > Some people tend to say it's coming from the linux-aio area [1], but I > >> >> > am not sure. > >> >> > 1st I thought this is a Linux-next problem but I am seeing it also > >> >> > with my rc-kernels. > >> >> > For parts of aio there is a patch discussed in [2]. > >> >> > The experimental patchset of Ken from [3] made the "aio" call-trace go > >> >> > away here. > >> >> > > >> >> > I tried also a patch pending in peterz/queue.git#sched/core from Eric Sandeen. > >> >> > It's "check for stack overflow in ___might_sleep". > >> >> > Unfortunately, it did not help in case of my loop-mq tests. > >> >> > ( BTW, this is touching ___might_sleep() (note: triple-underscore VS. > >> >> > affected __might_sleep() <--- double-underscrore). ) > >> >> > > >> >> > Let me hear your feedback. > >> >> > > >> >> > Have more fun! > >> >> > > >> >> > - Sedat - > >> >> > > >> >> > [1] http://marc.info/?l=linux-aio&m=142033318411355&w=2 > >> >> > [2] http://marc.info/?l=linux-aio&m=142035799514685&w=2 > >> >> > [3] http://evilpiepirate.org/git/linux-bcache.git/log/?h=aio_ring_fix > >> >> > [4] http://git.kernel.org/cgit/linux/kernel/git/peterz/queue.git/patch/?id=48e615e4c3ebed488fecb6bfb40b372151f62db2 > >> >> > >> >> [ CC Takashi ] > >> >> > >> >> >From [1]: > >> >> ... > >> >> > >> >> Just "me too" (but overlooked until recently). > >> >> > >> >> The cause is a mutex_lock() call right after prepare_to_wait() with > >> >> TASK_INTERRUPTIBLE in fanotify_read(). > >> >> > >> >> static ssize_t fanotify_read(struct file *file, char __user *buf, > >> >> size_t count, loff_t *pos) > >> >> { > >> >> .... > >> >> while (1) { > >> >> prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); > >> >> mutex_lock(&group->notification_mutex); > >> >> > >> >> I saw Peter already fixed a similar code in inotify_user.c by commit > >> >> e23738a7300a (but interestingly for a different reason, "Deal with > >> >> nested sleeps"). Supposedly a similar fix would be needed for > >> >> fanotify_user.c. > >> >> ... > >> >> > >> >> Can you explain why do you think the problem is in sched-fanotify? > >> >> > >> >> I tried to do such a "similiar" (quick) fix analog to the mentioned > >> >> "sched, inotify: Deal with nested sleeps" patch from Peter. > >> >> If I did correct... It does not make the call-trace go away here. > >> > > >> > Your code path is different from what Dave and I hit. Take a closer > >> > look at the stack trace. > >> > > >> > >> Yeah, you are right. > >> I looked again into the code (see thread "Linux 3.19-rc3", I am > >> reading offline). > >> > >> As said aio_ring_fix patchset and especially [1] fixed the issue for me. > >> > >> Can you confirm Peter's new patch works-for-you? > > > > Yes, it seems working for me at the last time I tried. > > (BTW, you don't need to add #include ) > > > > Just one minute ago, I asked about that? > Can you explain that - included by another include? Well, the original code calls the stuff defined in linux/wait.h, so it's already there obviously. Takashi