From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752653AbdKWL07 (ORCPT ); Thu, 23 Nov 2017 06:26:59 -0500 Received: from mx2.suse.de ([195.135.220.15]:48611 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752083AbdKWL06 (ORCPT ); Thu, 23 Nov 2017 06:26:58 -0500 Date: Thu, 23 Nov 2017 12:26:54 +0100 From: Michal Hocko To: Tetsuo Handa Cc: syzbot , akpm@linux-foundation.org, hannes@cmpxchg.org, hillf.zj@alibaba-inc.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mgorman@techsingularity.net, minchan@kernel.org, shli@fb.com, syzkaller-bugs@googlegroups.com, ying.huang@intel.com, Al Viro , Dave Chinner Subject: Re: general protection fault in __list_del_entry_valid (2) Message-ID: <20171123112654.4yjlj5vbtk3lzyl3@dhcp22.suse.cz> References: <001a113f996099503a055e793dd3@google.com> <0e1109ef-6d4a-e873-a809-6548776a00f9@I-love.SAKURA.ne.jp> <20171121140500.bgkpwcdk2dxesao4@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171121140500.bgkpwcdk2dxesao4@dhcp22.suse.cz> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 21-11-17 15:05:00, Michal Hocko wrote: > [Cc Al and Dave - email thread starts http://lkml.kernel.org/r/001a113f996099503a055e793dd3@google.com] [...] > Something like the totally untested and possibly wrong > --- > diff --git a/fs/super.c b/fs/super.c > index 994db21f59bf..1eb850413fdf 100644 > --- a/fs/super.c > +++ b/fs/super.c > @@ -506,6 +506,11 @@ struct super_block *sget_userns(struct file_system_type *type, > s = alloc_super(type, (flags & ~SB_SUBMOUNT), user_ns); > if (!s) > return ERR_PTR(-ENOMEM); > + if (register_shrinker(&s->s_shrink)) { > + up_write(&s->s_umount); > + destroy_super(s); > + return ERR_PTR(-ENOMEM); > + } > goto retry; > } > > @@ -522,7 +527,6 @@ struct super_block *sget_userns(struct file_system_type *type, > hlist_add_head(&s->s_instances, &type->fs_supers); > spin_unlock(&sb_lock); > get_filesystem(type); > - register_shrinker(&s->s_shrink); > return s; > } This is not complete. I thought we would unregister the shrinker somewher in destroy_super path but this is not the case. I will send another patch along with other shrinkers registration fixes in a separate thread. -- Michal Hocko SUSE Labs