From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757593Ab1FQOLe (ORCPT ); Fri, 17 Jun 2011 10:11:34 -0400 Received: from moutng.kundenserver.de ([212.227.126.187]:64176 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753940Ab1FQOLd (ORCPT ); Fri, 17 Jun 2011 10:11:33 -0400 From: Arnd Bergmann To: Ralf Baechle Subject: Re: [AX25] inconsistent lock state Date: Fri, 17 Jun 2011 16:11:10 +0200 User-Agent: KMail/1.13.6 (Linux/3.0.0-rc1nosema+; KDE/4.6.3; x86_64; ; ) Cc: f6bvp , linux-kernel@vger.kernel.org, Linux Netdev List , linux-hams@vger.kernel.org References: <4B2CD772.1030106@upmc.fr> <201106171536.15660.arnd@arndb.de> <20110617135147.GA3470@linux-mips.org> In-Reply-To: <20110617135147.GA3470@linux-mips.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201106171611.10655.arnd@arndb.de> X-Provags-ID: V02:K0:NWeMWz0GEM1ctT1CtwmoPdoB9RtXUP68ur6tUm26ebv JN+yoYXLSGg3g4z7yRsaPrO/AfmOo4W90MZVIJlBLXMAyHv4Y2 +eEB7FtYizRzdkmKPJrl9Cv6MVFrvjWQUyyoUAKBF7EwCAsqu2 GWww/1FmXu+YEb1vrGeja5KbR1XtlaolvNBGaHmN2iXpbYjM+e nol/bYSDR5Wn3fLd1NV0Q== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 17 June 2011 15:51:48 Ralf Baechle wrote: > On Fri, Jun 17, 2011 at 03:36:15PM +0200, Arnd Bergmann wrote: > > (Removed Jarek from cc; his email bounces.) > > > The message hints that disc_data_lock is aquired with softirqs disabled, > > but does not itself disable softirqs, which can in rare circumstances > > lead to a deadlock. > > > > Does this fix it? > > If so, drivers/net/hamradio.c, function sp_get() would probably need the > equivalent fix. Same for drivers/net/ppp_async.c:ap_get() and sp_get() in > drivers/net/ppp_synctty.c. It seems that ppp_synctty.c is ok, it uses write_lock_irq() already, sixpack.c looks like it has the same bug as mkiss. I also realized after sending out the patch that only the write_lock needs to be changed to write_lock_bh, while read_lock can leave softirqs enabled because it can be called recursively. Arnd