Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757520AbXFUSgW (ORCPT ); Thu, 21 Jun 2007 14:36:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752974AbXFUSgP (ORCPT ); Thu, 21 Jun 2007 14:36:15 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:44472 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750711AbXFUSgN (ORCPT ); Thu, 21 Jun 2007 14:36:13 -0400 Date: Thu, 21 Jun 2007 11:35:21 -0700 (PDT) From: Linus Torvalds To: Oleg Nesterov cc: Benjamin Herrenschmidt , Davide Libenzi , Nicholas Miell , Linux Kernel Mailing List Subject: Re: Fix signalfd interaction with thread-private signals In-Reply-To: <20070621182340.GA92@tv-sign.ru> Message-ID: References: <1182127391.26853.207.camel@localhost.localdomain> <20070619091452.GA94@tv-sign.ru> <1182254988.26853.334.camel@localhost.localdomain> <20070619140646.GB27343@tv-sign.ru> <1182295473.26853.386.camel@localhost.localdomain> <20070620111415.GA91@tv-sign.ru> <20070621082509.GA88@tv-sign.ru> <20070621182340.GA92@tv-sign.ru> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1055 Lines: 32 On Thu, 21 Jun 2007, Oleg Nesterov wrote: > > Yes, the target thread is the one that caused the SIGSEGV, it sends the signal > to itself. entry.S:ret_from_exception should notice this signal and _dequeue_ > it, no? This signal could be stealed by signal(SIG_IGN) which runs after it > was delivered. Right. But it will dequeue it by *taking* it. IOW, this has absolutely nothing to do with signalfd. That's all I mean. > My point was that it is _possible_ to steal a thread-local SIGSEGV even without > signalfd, nothing bad should happen. That makes no sense. You don't "steal" it. You take it. It's what SIGSEGV (and _any_ signal) has always been about. You get the signal, enter the signal handler, and handle it. No "stealing". No signalfd, no *nothing*. Just normal signal behaviour. Linus - 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/