From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932478AbbBBFye (ORCPT ); Mon, 2 Feb 2015 00:54:34 -0500 Received: from ipmail06.adl2.internode.on.net ([150.101.137.129]:4298 "EHLO ipmail06.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751257AbbBBFyb (ORCPT ); Mon, 2 Feb 2015 00:54:31 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av8WAHYQz1R5LHOVPGdsb2JhbABbgwaBK4Iyg3mrcQEBAQEBAQaYKQICAQECgRZEAQEBAQEGAQEBATg7hAwBAQEEJxMcIxAIAxUDCSUPBSUDBxoTG4gR0n8BAQEHAgEfGIVsiXQHhCkFmC2KNYgogiQcgWQqMYJCAQEB Date: Mon, 2 Feb 2015 16:54:29 +1100 From: Dave Chinner To: Linus Torvalds Cc: linux-aio@kvack.org, Kernel Mailing List , Benjamin LaHaise Subject: Re: [GIT PULL] aio: fix sleeping while TASK_INTERRUPTIBLE Message-ID: <20150202055429.GH4251@dastard> References: <20150201144058.GM2974@kvack.org> <20150201221458.GN2974@kvack.org> <20150202001628.GO2974@kvack.org> <20150202052944.GF4251@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 01, 2015 at 09:36:52PM -0800, Linus Torvalds wrote: > On Feb 1, 2015 9:29 PM, "Dave Chinner" wrote: > > > > So what's the outcome here? I'm running v3.19-rc7 kernel and > > xfstests::generic/036 is still tripping this warning from the aio > > code: > > So for the aio case, I suspect just adding a sched_annotate_sleep() is the > solution. But considering that there are apparently some other cases of > this warning that are nobody seems to bother fixing, it may just be that > I'll have to disable the warning entirely for 3.19 (and then maybe > re-enable it during the merge window and see if that makes anybody care > again) Simple enough - the patch below removes the warning from generic/036 for me. Cheers, Dave. -- Dave Chinner david@fromorbit.com aio: annotate aio_read_event_ring for sleep patterns From: Dave Chinner Under CONFIG_DEBUG_ATOMIC_SLEEP=y, aio_read_event_ring() will throw warnings like the following due to being called from wait_event context: WARNING: CPU: 0 PID: 16006 at kernel/sched/core.c:7300 __might_sleep+0x7f/0x90() do not call blocking ops when !TASK_RUNNING; state=1 set at [] prepare_to_wait_event+0x63/0x110 Modules linked in: CPU: 0 PID: 16006 Comm: aio-dio-fcntl-r Not tainted 3.19.0-rc6-dgc+ #705 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffffffff821c0372 ffff88003c117cd8 ffffffff81daf2bd 000000000000d8d8 ffff88003c117d28 ffff88003c117d18 ffffffff8109beda ffff88003c117cf8 ffffffff821c115e 0000000000000061 0000000000000000 00007ffffe4aa300 Call Trace: [] dump_stack+0x4c/0x65 [] warn_slowpath_common+0x8a/0xc0 [] warn_slowpath_fmt+0x46/0x50 [] ? prepare_to_wait_event+0x63/0x110 [] ? prepare_to_wait_event+0x63/0x110 [] __might_sleep+0x7f/0x90 [] mutex_lock+0x24/0x45 [] aio_read_events+0x4c/0x290 [] read_events+0x1ec/0x220 [] ? prepare_to_wait_event+0x110/0x110 [] ? hrtimer_get_res+0x50/0x50 [] SyS_io_getevents+0x4d/0xb0 [] system_call_fastpath+0x12/0x17 ---[ end trace bde69eaf655a4fea ]--- There is not actually a bug here, so annotate the code to tell the debug logic that everything is just fine and not to fire a false positive. Signed-off-by: Dave Chinner --- fs/aio.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/aio.c b/fs/aio.c index 1b7893e..3176d6c 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1140,6 +1140,7 @@ static long aio_read_events_ring(struct kioctx *ctx, long ret = 0; int copy_ret; + sched_annotate_sleep(); mutex_lock(&ctx->ring_lock); /* Access to ->ring_pages here is protected by ctx->ring_lock. */