From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756316AbXF0HQV (ORCPT ); Wed, 27 Jun 2007 03:16:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751999AbXF0HQJ (ORCPT ); Wed, 27 Jun 2007 03:16:09 -0400 Received: from mx12.go2.pl ([193.17.41.142]:45017 "EHLO poczta.o2.pl" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751973AbXF0HQH (ORCPT ); Wed, 27 Jun 2007 03:16:07 -0400 Date: Wed, 27 Jun 2007 09:24:15 +0200 From: Jarek Poplawski To: Andrew Morton Cc: "Wessel\, Jason" , Folkert van Heusden , linux-kernel@vger.kernel.org, Thomas Gleixner , stable@kernel.org, netdev@vger.kernel.org Subject: [PATCH] Re: [2.6.21.1] soft lockup when removing netconsole module Message-ID: <20070627072415.GA1899@ff.dom.local> References: <20070626160753.f86d8803.akpm@linux-foundation.org> <7ED098B05D69FE41B380586BF1474DBA441F47@ala-mail08.corp.ad.wrs.com> <20070626180000.5974e942.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070626180000.5974e942.akpm@linux-foundation.org> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 26, 2007 at 06:00:00PM -0700, Andrew Morton wrote: > On Tue, 26 Jun 2007 17:46:13 -0700 "Wessel, Jason" wrote: ... > > > Everything went quiet? > > > > > > If this patch has been tested and fixes the bug, can you > > > please send a version which is ready for merging? (ie: add a > > > suitable description of what it does). > > > > > > > > > > I mailed Jarek separately. > > > > I had tested the patch with netconsole and kgdb and it does in fact fix > > the problem that was reported. > > OK, thanks. Please don't mail people separately! > > I queued this up with a null changelog for now. > I pasted here this queued version - only the changelog is added. Regards, Jarek P. ------------------------------------------------------ Subject: netconsole: fix soft lockup (2.6.21) and memory leak when removing module From: Jarek Poplawski #1 Until kernel ver. 2.6.21 (including) cancel_rearming_delayed_work() required a work function should always (unconditionally) rearm with delay > 0 - otherwise it would endlessly loop. This patch replaces this function with cancel_delayed_work(). Later kernel versions don't require this, so here it's only for uniformity. #2 After deleting a timer in cancel_[rearming_]delayed_work() there could stay a last skb queued in npinfo->txq causing a memory leak after kfree(npinfo). Initial patch & testing by: Jason Wessel Signed-off-by: Jarek Poplawski Signed-off-by: Andrew Morton --- net/core/netpoll.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff -puN net/core/netpoll.c~netconsole-fix-soft-lockup-when-removing-module net/core/netpoll.c --- a/net/core/netpoll.c~netconsole-fix-soft-lockup-when-removing-module +++ a/net/core/netpoll.c @@ -72,7 +72,8 @@ static void queue_process(struct work_st netif_tx_unlock(dev); local_irq_restore(flags); - schedule_delayed_work(&npinfo->tx_work, HZ/10); + if (atomic_read(&npinfo->refcnt)) + schedule_delayed_work(&npinfo->tx_work, HZ/10); return; } netif_tx_unlock(dev); @@ -785,9 +786,15 @@ void netpoll_cleanup(struct netpoll *np) if (atomic_dec_and_test(&npinfo->refcnt)) { skb_queue_purge(&npinfo->arp_tx); skb_queue_purge(&npinfo->txq); - cancel_rearming_delayed_work(&npinfo->tx_work); + cancel_delayed_work(&npinfo->tx_work); flush_scheduled_work(); + /* clean after last, unfinished work */ + if (!skb_queue_empty(&npinfo->txq)) { + struct sk_buff *skb; + skb = __skb_dequeue(&npinfo->txq); + kfree_skb(skb); + } kfree(npinfo); } }