From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752589AbdCBMZV convert rfc822-to-8bit (ORCPT ); Thu, 2 Mar 2017 07:25:21 -0500 Received: from smtp.ctxuk.citrix.com ([185.25.65.24]:59796 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750892AbdCBMZR (ORCPT ); Thu, 2 Mar 2017 07:25:17 -0500 X-IronPort-AV: E=Sophos;i="5.35,231,1484006400"; d="scan'208";a="41736549" From: Paul Durrant To: "'Juergen Gross'" , Wei Liu CC: Igor Druzhinin , xen-devel , Linux Kernel Mailing List , "netdev@vger.kernel.org" , Boris Ostrovsky , "David Miller" Subject: RE: BUG due to "xen-netback: protect resource cleaning on XenBus disconnect" Thread-Topic: BUG due to "xen-netback: protect resource cleaning on XenBus disconnect" Thread-Index: AQHSk0wasWQs+Kw3fUC5DEz73BBuRqGBY5mAgAABpICAABKNwA== Date: Thu, 2 Mar 2017 12:19:35 +0000 Message-ID: <6e79cc86f623446aa432a35aa8305807@AMSPEX02CL03.citrite.net> References: <75c81731-e4a7-bde1-c4fd-a52e97b820a0@suse.com> <20170302120653.dce2mehbmhyxsiow@citrix.com> <0e503a09-fbbb-02aa-152b-e4eaf3122a56@suse.com> In-Reply-To: <0e503a09-fbbb-02aa-152b-e4eaf3122a56@suse.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Juergen Gross [mailto:jgross@suse.com] > Sent: 02 March 2017 12:13 > To: Wei Liu > Cc: Igor Druzhinin ; xen-devel devel@lists.xenproject.org>; Linux Kernel Mailing List kernel@vger.kernel.org>; netdev@vger.kernel.org; Boris Ostrovsky > ; David Miller ; Paul > Durrant > Subject: Re: BUG due to "xen-netback: protect resource cleaning on XenBus > disconnect" > > On 02/03/17 13:06, Wei Liu wrote: > > On Thu, Mar 02, 2017 at 12:56:20PM +0100, Juergen Gross wrote: > >> With commits f16f1df65 and 9a6cdf52b we get in our Xen testing: > >> > >> [ 174.512861] switch: port 2(vif3.0) entered disabled state > >> [ 174.522735] BUG: sleeping function called from invalid context at > >> /home/build/linux-linus/mm/vmalloc.c:1441 > >> [ 174.523451] in_atomic(): 1, irqs_disabled(): 0, pid: 28, name: xenwatch > >> [ 174.524131] CPU: 1 PID: 28 Comm: xenwatch Tainted: G W > >> 4.10.0upstream-11073-g4977ab6-dirty #1 > >> [ 174.524819] Hardware name: MSI MS-7680/H61M-P23 (MS-7680), BIOS > V17.0 > >> 03/14/2011 > >> [ 174.525517] Call Trace: > >> [ 174.526217] show_stack+0x23/0x60 > >> [ 174.526899] dump_stack+0x5b/0x88 > >> [ 174.527562] ___might_sleep+0xde/0x130 > >> [ 174.528208] __might_sleep+0x35/0xa0 > >> [ 174.528840] ? _raw_spin_unlock_irqrestore+0x13/0x20 > >> [ 174.529463] ? __wake_up+0x40/0x50 > >> [ 174.530089] remove_vm_area+0x20/0x90 > >> [ 174.530724] __vunmap+0x1d/0xc0 > >> [ 174.531346] ? delete_object_full+0x13/0x20 > >> [ 174.531973] vfree+0x40/0x80 > >> [ 174.532594] set_backend_state+0x18a/0xa90 > >> [ 174.533221] ? dwc_scan_descriptors+0x24d/0x430 > >> [ 174.533850] ? kfree+0x5b/0xc0 > >> [ 174.534476] ? xenbus_read+0x3d/0x50 > >> [ 174.535101] ? xenbus_read+0x3d/0x50 > >> [ 174.535718] ? xenbus_gather+0x31/0x90 > >> [ 174.536332] ? ___might_sleep+0xf6/0x130 > >> [ 174.536945] frontend_changed+0x6b/0xd0 > >> [ 174.537565] xenbus_otherend_changed+0x7d/0x80 > >> [ 174.538185] frontend_changed+0x12/0x20 > >> [ 174.538803] xenwatch_thread+0x74/0x110 > >> [ 174.539417] ? woken_wake_function+0x20/0x20 > >> [ 174.540049] kthread+0xe5/0x120 > >> [ 174.540663] ? xenbus_printf+0x50/0x50 > >> [ 174.541278] ? __kthread_init_worker+0x40/0x40 > >> [ 174.541898] ret_from_fork+0x21/0x2c > >> [ 174.548635] switch: port 2(vif3.0) entered disabled state > >> > >> I believe calling vfree() when holding a spin_lock isn't a good idea. > >> > > > > Use vfree_atomic instead? > > Hmm, isn't this overkill here? > > You can just set a local variable with the address and do vfree() after > releasing the lock. > Yep, that's what I was thinking. Patch coming shortly. Paul > > Juergen