Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756858AbXEaBax (ORCPT ); Wed, 30 May 2007 21:30:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754264AbXEaBaq (ORCPT ); Wed, 30 May 2007 21:30:46 -0400 Received: from ms-smtp-03.nyroc.rr.com ([24.24.2.57]:57518 "EHLO ms-smtp-03.nyroc.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753942AbXEaBap (ORCPT ); Wed, 30 May 2007 21:30:45 -0400 Subject: Re: [BUG] futex_unlock_pi() hurts my brain and may cause application deadlock From: Steven Rostedt To: john stultz Cc: lkml , Ingo Molnar , Thomas Gleixner , Sripathi Kodi In-Reply-To: <1180572567.6126.44.camel@localhost.localdomain> References: <1180572567.6126.44.camel@localhost.localdomain> Content-Type: text/plain Date: Wed, 30 May 2007 21:29:53 -0400 Message-Id: <1180574993.21781.22.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 816 Lines: 28 On Wed, 2007-05-30 at 17:49 -0700, john stultz wrote: > ... > retry_locked: > /* > * To avoid races, try to do the TID -> 0 atomic transition > * again. If it succeeds then we can return without waking > * anyone else up: > */ > if (!(uval & FUTEX_OWNER_DIED)) { > pagefault_disable(); > uval = futex_atomic_cmpxchg_inatomic(uaddr, current->pid, 0); > pagefault_enable(); > } My question is to all the futex gurus out there. This code is in futex_unlock_pi. Can the owner of the mutex really die? Isn't the owner the one doing the unlock? -- Steve - 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/