From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935006AbcIPMuA (ORCPT ); Fri, 16 Sep 2016 08:50:00 -0400 Received: from mx2.suse.de ([195.135.220.15]:46563 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754814AbcIPMtw (ORCPT ); Fri, 16 Sep 2016 08:49:52 -0400 Date: Fri, 16 Sep 2016 14:49:48 +0200 From: Jan Kara To: Guenter Roeck Cc: Jan Kara , "linux-kernel@vger.kernel.org" , Andrew Morton Subject: Re: Crashes in next-20160915 (BUG at fs/notify/notification.c:66!) Message-ID: <20160916124948.GG24269@quack2.suse.cz> References: <20160916064521.GF24269@quack2.suse.cz> <6ae57328-ab25-8798-51f9-9a30d9c2af70@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6ae57328-ab25-8798-51f9-9a30d9c2af70@roeck-us.net> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 16-09-16 04:10:38, Guenter Roeck wrote: > On 09/15/2016 11:45 PM, Jan Kara wrote: > >Hi, > > > >On Thu 15-09-16 19:20:10, Guenter Roeck wrote: > >>I see various architectures crashing in -next with the following error. > >> > >>------------[ cut here ]------------ > >>kernel BUG at fs/notify/notification.c:66! > > > >Thanks for report! > > > >... > > > >>Call Trace: > >> [] inotify_poll+0x42/0x70 > >> [] SyS_epoll_ctl+0x84a/0xf60 > >> [] ? ep_send_events_proc+0x180/0x180 > >> [] entry_SYSCALL_64_fastpath+0x13/0x8f > >>Code: 90 90 0f 1f 44 00 00 55 b8 01 00 00 00 48 89 e5 0f c1 05 bb e4 d4 00 83 c0 01 5d c3 66 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 <0f> 0b 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 10 48 > >>RIP [] fsnotify_notify_queue_is_empty+0x9/0x10 > >> RSP > >>---[ end trace 7dc4a27003f0b575 ]--- > >> > >>I didn't bisect, but I would guess the culprit is one of the new patches in the > >>affected file. > >> > >>22e9cf146d3b fanotify: fix possible false warning when freeing events > >>ced89591817c fsnotify: convert notification_mutex to a spinlock > >>f82fa3d0e7f5 fsnotify: drop notification_mutex before destroying event > >>782fbc7e8685 fanotify: fix list corruption in fanotify_get_response() > >>56cf1c8a1b35 fsnotify: add a way to stop queueing events on group shutdown > > > >Yes, very likely my patches cause this. But it must be some config issue > >because my test machine does not hit this and the code is "obviously > >correct" - famous last words ;). I've seen zero-day robot complain as well > >so I'll try the config it had sent me and see what's going on (likely > >spin_is_locked() does not do what I thought under some configs...). > > > > Your builds are probably all SMP builds. Looks like this happens if SMP > is disabled. Right, that was the problem. spin_is_locked() without CONFIG_SPINLOCK_DEBUG returns always 0. Honza -- Jan Kara SUSE Labs, CR