Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754553AbbGVFeT (ORCPT ); Wed, 22 Jul 2015 01:34:19 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:23617 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751836AbbGVFeR (ORCPT ); Wed, 22 Jul 2015 01:34:17 -0400 Message-ID: <55AF2B4F.7050609@oracle.com> Date: Wed, 22 Jul 2015 13:34:07 +0800 From: Bob Liu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130308 Thunderbird/17.0.4 MIME-Version: 1.0 To: =?windows-1252?Q?Roger_Pau_Monn=E9?= CC: xen-devel@lists.xenproject.org, david.vrabel@citrix.com, linux-kernel@vger.kernel.org, konrad.wilk@oracle.com Subject: Re: [PATCH 2/3] xen-blkfront: rm BUG_ON(info->feature_persistent) in blkif_free References: <1437449441-2964-1-git-send-email-bob.liu@oracle.com> <1437449441-2964-2-git-send-email-bob.liu@oracle.com> <55AE1019.6080906@citrix.com> <55AF1F76.40400@oracle.com> In-Reply-To: <55AF1F76.40400@oracle.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4429 Lines: 87 On 07/22/2015 12:43 PM, Bob Liu wrote: > > On 07/21/2015 05:25 PM, Roger Pau Monn? wrote: >> El 21/07/15 a les 5.30, Bob Liu ha escrit: >>> This BUG_ON() in blkif_free() is incorrect, because indirect page can be added >>> to list info->indirect_pages in blkif_completion() no matter feature_persistent >>> is true or false. >>> >>> Signed-off-by: Bob Liu >> >> Acked-by: Roger Pau Monn? >> >> This was probably an oversight from when blkif_completion was changed to >> check for gnttab_query_foreign_access. It should be backported to stable >> trees. >> > > Sorry, this patch is buggy and I haven't figure out why. > > general protection fault: 0000 [#1] SMP > Modules linked in: > CPU: 0 PID: 39 Comm: xenwatch Tainted: G W 4.1.0-rc3-00003-g718cf80-dirty #67 > Hardware name: Xen HVM domU, BIOS 4.5.0-rc 11/23/2014 > task: ffff880283f4eca0 ti: ffff880283fb4000 task.ti: ffff880283fb4000 > RIP: 0010:[] [] blkif_free+0x162/0x5a9 > RSP: 0018:ffff880283fb7c48 EFLAGS: 00010087 > RAX: dead000000200200 RBX: ffff880141400000 RCX: 0000000000000000 > RDX: dead000000100100 RSI: dead000000100100 RDI: ffff88028f418bb8 > RBP: ffff880283fb7ca8 R08: dead000000200200 R09: 0000000000000001 > R10: 0000000000000001 R11: 0000000000000000 R12: ffff8801414481c8 > R13: dead0000001000e0 R14: ffff8801414481b8 R15: ffffea0000000000 > FS: 0000000000000000(0000) GS:ffff88028f400000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000001582e08 CR3: 000000013345b000 CR4: 00000000001406f0 > Stack: > ffff880023aa8420 0000000000000286 ffff880283fb7cb7 ffff880023aa8420 > ffff8800363fe240 ffffffff81862c50 ffff880283fb7ce8 ffff880023aa8440 > ffffffff81870000 ffff880023aa8400 ffff880141400000 ffff880141400008 > Call Trace: > [] blkfront_remove+0x4c/0xff > [] xenbus_dev_remove+0x76/0xb0 > [] __device_release_driver+0x84/0xf8 > [] device_release_driver+0x1e/0x2b > [] bus_remove_device+0x12c/0x141 > [] device_del+0x161/0x1e5 > [] ? xenbus_thread+0x239/0x239 > [] device_unregister+0x43/0x4f > [] xenbus_dev_changed+0x82/0x17f > [] ? xenbus_otherend_changed+0xf0/0xff > [] frontend_changed+0x43/0x48 > [] xenwatch_thread+0xf9/0x127 > [] ? add_wait_queue+0x44/0x44 > [] kthread+0xcd/0xd5 > [] ? alloc_pid+0xe8/0x492 > [] ? kthread_freezable_should_stop+0x48/0x48 > [] ret_from_fork+0x42/0x70 > [] ? kthread_freezable_should_stop+0x48/0x48 > Code: 04 00 4c 8b 28 48 8d 78 e0 49 83 ed 20 eb 3d 48 8b 47 28 48 8b 57 20 48 be 00 01 10 00 00 00 ad de 49 b8 00 02 20 00 00 00 ad de <48> 89 42 08 48 89 10 48 89 77 20 4c 89 47 28 31 f6 e8 26 7d cf > RIP [] blkif_free+0x162/0x5a9 > RSP > ---[ end trace 5321d7f1ef8414d0 ]--- > The right fix should be: --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1124,8 +1124,10 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, * Add the used indirect page back to the list of * available pages for indirect grefs. */ - indirect_page = pfn_to_page(s->indirect_grants[i]->pfn); - list_add(&indirect_page->lru, &info->indirect_pages); + if (!info->feature_persistent) { + indirect_page = pfn_to_page(s->indirect_grants[i]->pfn); + list_add(&indirect_page->lru, &info->indirect_pages); + } s->indirect_grants[i]->gref = GRANT_INVALID_REF; list_add_tail(&s->indirect_grants[i]->node, &info->grants); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/