From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964885AbaFCULA (ORCPT ); Tue, 3 Jun 2014 16:11:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34001 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934202AbaFCUK4 (ORCPT ); Tue, 3 Jun 2014 16:10:56 -0400 Date: Tue, 3 Jun 2014 22:09:38 +0200 From: Oleg Nesterov To: Steven Rostedt Cc: Linus Torvalds , LKML , Thomas Gleixner , Peter Zijlstra , Andrew Morton , Ingo Molnar , Clark Williams Subject: Re: [BUG] signal: sighand unprotected when accessed by /proc Message-ID: <20140603200938.GA3384@redhat.com> References: <20140603130233.658a6a3c@gandalf.local.home> <20140603172632.GA27956@redhat.com> <20140603160524.7895f225@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140603160524.7895f225@gandalf.local.home> 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 Steven, I am already sleeping, probably I just need to re-read your email tomorrow, but... On 06/03, Steven Rostedt wrote: > > When we convert the spin_lock into a rtmutex, when we hit the lock and > it was contended (the task was in the process of exiting and it takes > the lock to set tsk->sighand to NULL), instead of spinning, the task > adds itself to the lock->wait_list and goes to sleep. This is clear, > Now, if that lock is released and reused (I didn't trace other tasks > allocating these locks), it reinitializes the lock->wait_list. How? From where? This should be done by sighand_ctor() only? Oleg.