Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762161Ab3DCFfj (ORCPT ); Wed, 3 Apr 2013 01:35:39 -0400 Received: from mail-pb0-f47.google.com ([209.85.160.47]:62789 "EHLO mail-pb0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752107Ab3DCFfi (ORCPT ); Wed, 3 Apr 2013 01:35:38 -0400 Date: Tue, 2 Apr 2013 22:35:34 -0700 From: Greg Kroah-Hartman To: Ming Lei Cc: Dave Jones , linux-kernel@vger.kernel.org, Sasha Levin Subject: Re: [PATCH] sysfs: check if one entry has been removed before freeing Message-ID: <20130403053534.GA8091@kroah.com> References: <1364957903-10341-1-git-send-email-ming.lei@canonical.com> <20130403030403.GA26913@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1443 Lines: 35 On Wed, Apr 03, 2013 at 11:52:39AM +0800, Ming Lei wrote: > On Wed, Apr 3, 2013 at 11:04 AM, Dave Jones wrote: > > On Wed, Apr 03, 2013 at 10:58:23AM +0800, Ming Lei wrote: > > > > > diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c > > > index 1bf016b..328ef9b 100644 > > > --- a/fs/sysfs/dir.c > > > +++ b/fs/sysfs/dir.c > > > @@ -268,6 +268,13 @@ void release_sysfs_dirent(struct sysfs_dirent * sd) > > > */ > > > parent_sd = sd->s_parent; > > > > > > + if (unlikely(!(sd->s_flags & SYSFS_FLAG_REMOVED))) { > > > + printk(KERN_ERR "sysfs: free using entry: %s/%s\n", > > > + parent_sd ? parent_sd->s_name : "", > > > + sd->s_name); > > > + BUG(); > > > + } > > > > Please use WARN instead of BUG. For an in-ram filesystem like > > sysfs, there's no real reason to lock-up the machine in this way > > making it harder to debug. > > If WARN is used, the freed memory will be allocated to other > kernel components, then sysfs may change the memory and cause > destruction, so maybe it is better to use BUG to stop kernel. No, it's never ok to call BUG(), sorry, please fix this. greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/