From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754187Ab2JSKnI (ORCPT ); Fri, 19 Oct 2012 06:43:08 -0400 Received: from mail-ea0-f174.google.com ([209.85.215.174]:64433 "EHLO mail-ea0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750878Ab2JSKnG (ORCPT ); Fri, 19 Oct 2012 06:43:06 -0400 Subject: Re: [PATCH v4] posix timers: allocate timer id per process From: Eric Dumazet To: Stanislav Kinsbursky Cc: "peterz@infradead.org" , "mingo@redhat.com" , "tglx@linutronix.de" , "devel@openvz.org" , "linux-kernel@vger.kernel.org" , Pavel Emelianov In-Reply-To: <50811FA6.8000709@parallels.com> References: <20121019074912.10745.339.stgit@localhost.localdomain> <1350633401.2293.245.camel@edumazet-glaptop> <50811FA6.8000709@parallels.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 19 Oct 2012 12:43:03 +0200 Message-ID: <1350643383.2293.436.camel@edumazet-glaptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2012-10-19 at 13:38 +0400, Stanislav Kinsbursky wrote: > 19.10.2012 11:56, Eric Dumazet пишет: > > I wonder if some applications relied on our idr, assuming they would get > > low values for their timer id. > > (We could imagine some applications use a table indexed by the timer id) > > Hmm. > Probably, this particular case can be optimised by tuning min_id to id of > releasing timer (if id of this timer is less than current->signal min_id). > Does this approach solves the issue you mentioned above? Not generally, but I am not sure we want a per signal_struct idr ;) Really that should be clearly explained in the changelog, so that buggy applications can have a clue of what happened. When we changed UDP source port selection being random instead of sequential, maybe this broke some applications. That was an implementation choice (with security impact).