Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753695AbaBOSpi (ORCPT ); Sat, 15 Feb 2014 13:45:38 -0500 Received: from mx1.redhat.com ([209.132.183.28]:19757 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753562AbaBOSph (ORCPT ); Sat, 15 Feb 2014 13:45:37 -0500 Date: Sat, 15 Feb 2014 19:45:31 +0100 From: Oleg Nesterov To: Al Viro Cc: Linus Torvalds , Dave Chinner , Dave Jones , Eric Sandeen , Linux Kernel , xfs@oss.sgi.com Subject: Re: 3.14-rc2 XFS backtrace because irqs_disabled. Message-ID: <20140215184531.GA27314@redhat.com> References: <20140213174020.GA14455@redhat.com> <20140215052531.GX18016@ZenIV.linux.org.uk> <20140215142700.GA15540@redhat.com> <20140215152251.GY18016@ZenIV.linux.org.uk> <20140215153631.GZ18016@ZenIV.linux.org.uk> <20140215155838.GA18016@ZenIV.linux.org.uk> <20140215174345.GA24799@redhat.com> <20140215180520.GC18016@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140215180520.GC18016@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/15, Al Viro wrote: > > On Sat, Feb 15, 2014 at 06:43:45PM +0100, Oleg Nesterov wrote: > > > So basically we want a different condition for "can we just go ahead and > > > free that sucker", right? Instead of "it's on the list, shan't free it" > > > it ought to be something like "it's on the list or it is referenced by > > > ksiginfo". Locking will be interesting, though... ;-/ > > > > I guess yes... send_sigqueue() checks list_empty() too, probably nobody else. > > The trouble being, we might end up with > Q picked by collect_signal and and stuff into ksiginfo > Q resubmitted by timer code In this case the timer code should simply inc ->si_overrun and do nothing. IOW, list_empty() should be turned into is_queued(), and is_queued() should be true until dismiss_siginfo() which should also do do_schedule_next_timer(). I think. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/