From: Andrew Morton Subject: Re: [PATCH] Check for error returned by kthread_create on creating journal thread Date: Fri, 20 Apr 2007 15:38:09 -0700 Message-ID: <20070420153809.8ce9a662.akpm@linux-foundation.org> References: <4623289A.1000101@sw.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: sct@redhat.com, linux-ext4@vger.kernel.org, Linux Kernel Mailing List , devel@openvz.org To: Pavel Emelianov Return-path: Received: from smtp1.linux-foundation.org ([65.172.181.25]:36929 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751615AbXDTWi0 (ORCPT ); Fri, 20 Apr 2007 18:38:26 -0400 In-Reply-To: <4623289A.1000101@sw.ru> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Mon, 16 Apr 2007 11:41:14 +0400 Pavel Emelianov wrote: > If the thread failed to create the subsequent wait_event > will hang forever. > > This is likely to happen if kernel hits max_threads limit. > > Will be critical for virtualization systems that limit the > number of tasks and kernel memory usage within the container. > > > [diff-jbd-check-start-journal-thread-return-value text/plain (1.7KB)] > --- ./fs/jbd/journal.c.jbdthreads 2007-04-16 11:17:36.000000000 +0400 > +++ ./fs/jbd/journal.c 2007-04-16 11:30:09.000000000 +0400 > @@ -211,10 +211,16 @@ end_loop: > return 0; > } > > -static void journal_start_thread(journal_t *journal) > +static int journal_start_thread(journal_t *journal) > { > - kthread_run(kjournald, journal, "kjournald"); > + struct task_struct *t; > + > + t = kthread_run(kjournald, journal, "kjournald"); > + if (IS_ERR(t)) > + return PTR_ERR(t); > + > wait_event(journal->j_wait_done_commit, journal->j_task != 0); > + return 0; > } Thanks. Please don't forget those Signed-off-by:s I assume that you runtime tested this and that the mount failed in an appropriate fashion?