From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Paris Subject: Re: [PATCH] fanotify: Do check against max_marks and increase number of group marks atomically Date: Tue, 09 Nov 2010 15:21:45 -0500 Message-ID: <1289334105.3083.30.camel@localhost.localdomain> References: <20101109181904.GB5867@lsanfilippo.unix.rd.tt.avira.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org To: Lino Sanfilippo Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63686 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752911Ab0KIUVt (ORCPT ); Tue, 9 Nov 2010 15:21:49 -0500 In-Reply-To: <20101109181904.GB5867@lsanfilippo.unix.rd.tt.avira.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, 2010-11-09 at 19:19 +0100, Lino Sanfilippo wrote: > The number of group marks is checked against max_marks and increased afterwards > in a non atomic way. This may result in 2 or more processes passing the check > at the same time and increasing the number of group marks above the max_marks > limit afterwards. > With this patch the check against max_marks is done in fsnotify_add_mark(), > after the group lock has been aquired to ensure that concurrent processes > cant exceed the group marks limit. > > Signed-off-by: Lino Sanfilippo applied to http://git.infradead.org/users/eparis/notify.git/ #for-next -Eric