Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754251Ab0FOD0S (ORCPT ); Mon, 14 Jun 2010 23:26:18 -0400 Received: from ozlabs.org ([203.10.76.45]:49191 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752041Ab0FOD0R (ORCPT ); Mon, 14 Jun 2010 23:26:17 -0400 Date: Tue, 15 Jun 2010 13:26:08 +1000 From: Paul Mackerras To: Andrew Morton Cc: tytso@mit.edu, Salman , mingo@elte.hu, linux-kernel@vger.kernel.org, peterz@infradead.org, tytso@google.com, torvalds@linux-foundation.org, walken@google.com, Chen Liqin , Lennox Wu Subject: Re: [PATCH] Fix a race in pid generation that causes pids to be reused immediately. Message-ID: <20100615032608.GB30479@drongo> References: <20100611224902.5039.60134.stgit@bumblebee1.mtv.corp.google.com> <20100614165851.6bdfe485.akpm@linux-foundation.org> <20100615005619.GI6666@thunk.org> <20100614185556.afdc5304.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100614185556.afdc5304.akpm@linux-foundation.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 643 Lines: 16 On Mon, Jun 14, 2010 at 06:55:56PM -0700, Andrew Morton wrote: > > kernel/sched_clock.c: if (cmpxchg64(&scd->clock, old_clock, clock) != old_cloc > > I guess that'll flush out any stragglers. And break most non-x86 32-bit architectures, including 32-bit powerpc. Fortunately that code is only used if CONFIG_HAVE_UNSTABLE_SCHED_CLOCK is set, and it looks like only x86 and ia64 set it. Paul. -- 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/