Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751715AbbGaJ0x (ORCPT ); Fri, 31 Jul 2015 05:26:53 -0400 Received: from casper.infradead.org ([85.118.1.10]:59265 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750786AbbGaJ0v (ORCPT ); Fri, 31 Jul 2015 05:26:51 -0400 Date: Fri, 31 Jul 2015 11:26:42 +0200 From: Peter Zijlstra To: Vince Weaver Cc: Ingo Molnar , linux-kernel@vger.kernel.org, eranian@google.com, Paul Mackerras , Arnaldo Carvalho de Melo Subject: Re: [patch] inherited events not signalling parent on overflow Message-ID: <20150731092642.GT25159@twins.programming.kicks-ass.net> References: <20150529063650.GA22568@gmail.com> <1434011521.1495.71.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1451 Lines: 32 On Fri, Jul 31, 2015 at 12:42:06AM -0400, Vince Weaver wrote: > On Thu, 11 Jun 2015, Peter Zijlstra wrote: > > > Right, I had a peek earlier at how fasync worked but came away confused. > > > > Today I seem to have had better luck. Installing fasync allocates memory > > and sets filp->f_flags |= FASYNC, which upon the demise of the file > > descriptor ensures the allocation is freed. > > > > Now for perf, we can have the events stick around for a while after the > > original FD is dead because of references from child events. With the > > above patch these events would still have a pointer into this free'd > > fasync. This is bad. > > > > A further problem with the patch is that if the parent changes its > > fasync state the children might lag and again have pointers into dead > > space. > > > > All is not lost though; does something like the below work? > > I had meant to reply to this earlier but maybe I forgot. > > I've been running with this patch for a month now and haven't had > problems, and it fixes the issue of inherited signals. So it no one else > has issues with the patch it would be nice if it could be pushed upstream. Great, thanks for testing. I'll go queue it. -- 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/