From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: fs: gpf in simple_setattr Date: Wed, 5 Mar 2014 13:45:36 +0100 Message-ID: <20140305124536.GA32371@quack.suse.cz> References: <52B23CEA.7090405@oracle.com> <52CD762B.7020600@oracle.com> <53123D81.6080003@oracle.com> <20140303214040.GA15265@quack.suse.cz> <53166920.709@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , Al Viro , linux-fsdevel@vger.kernel.org, LKML , Linus Torvalds To: Sasha Levin Return-path: Content-Disposition: inline In-Reply-To: <53166920.709@oracle.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Tue 04-03-14 19:00:32, Sasha Levin wrote: > On 03/03/2014 04:40 PM, Jan Kara wrote: > >On Sat 01-03-14 15:05:21, Sasha Levin wrote: > >>>ping again? > >>> > >>>I've been working on it, but don't see an obvious issue. > >>> > >>>It does look like an access to invalid memory easily doable from > >>>userspace, so it should probably get fixed soon... > > Hum, can you maybe dump the name in dentry passed to simple_setattr()? Or > >maybe even the whole path using dentry_path() (but not sure if that will > >be workable on half-torn-down fs)? Maybe it will give us a hint at which > >filesystem to look... > > It's just garbage, this is why I'm having a hard time making any progress with > this bug. OK, but that is strange because we hold a reference to the dentry so noone should free it. So dentry->d_name should be valid... Is the rest of the dentry also garbage? E.g. does dentry->d_inode still point to the inode we call __mark_inode_dirty() on? Is dentry->d_sb == dentry->d_inode->i_sb? Also if the inode isn't completely garbage, we can maybe infer something from inode->i_op - that should point to some statically allocated operations struct so we should be able to guess fs type from that. Honza -- Jan Kara SUSE Labs, CR