From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754204AbdGUJmP (ORCPT ); Fri, 21 Jul 2017 05:42:15 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:55154 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753995AbdGUJmN (ORCPT ); Fri, 21 Jul 2017 05:42:13 -0400 Date: Fri, 21 Jul 2017 11:42:05 +0200 (CEST) From: Thomas Gleixner To: James Bottomley cc: Steven Rostedt , LKML , linux-scsi , QLogic-Storage-Upstream@qlogic.com, martin.petersen@oracle.com Subject: Re: [BUG] lockdep splat with cpu_hotplug_lock In-Reply-To: <1500594526.3568.44.camel@HansenPartnership.com> Message-ID: References: <20170720193501.4f09499f@gandalf.local.home> <1500594526.3568.44.camel@HansenPartnership.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: multipart/mixed; BOUNDARY="8323329-1824905611-1500630127=:2077" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-1824905611-1500630127=:2077 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT On Thu, 20 Jul 2017, James Bottomley wrote: > [redirecting to linux-scsi] > On Thu, 2017-07-20 at 19:35 -0400, Steven Rostedt wrote: > > My tests triggered this splat on 4.13-rc1: > > > > Loading iSCSI transport class v2.0-870. > > QLogic NetXtreme II iSCSI Driver bnx2i v2.7.10.1 (Jul 16, 2014) > > iscsi: registered transport (bnx2i) > > > > ============================================ > > WARNING: possible recursive locking detected > > 4.13.0-rc1-test+ #2 Not tainted > > -------------------------------------------- > > swapper/0/1 is trying to acquire lock: > >  (cpu_hotplug_lock.rw_sem){++++++}, at: [] > > __cpuhp_setup_state+0x28/0x59 > > > > but task is already holding lock: > >  (cpu_hotplug_lock.rw_sem){++++++}, at: [] > > bnx2i_mod_init+0x134/0x209 > > > > other info that might help us debug this: > >  Possible unsafe locking scenario: > > > >        CPU0 > >        ---- > >   lock(cpu_hotplug_lock.rw_sem); > >   lock(cpu_hotplug_lock.rw_sem); > > It sounds like it's an annotation issue not an actual problem.  I've > added the correct list, so hopefully our usual enthusiasts can take a > look. Nope. It's a recursive locking/\ of cpuhotplug lock. I'll have a look on monday. Thanks, tglx --8323329-1824905611-1500630127=:2077--