From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:29747 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751348AbbKNCD5 (ORCPT ); Fri, 13 Nov 2015 21:03:57 -0500 Date: Fri, 13 Nov 2015 18:03:50 -0800 From: Liu Bo To: fdmanana@kernel.org Cc: linux-btrfs@vger.kernel.org, Filipe Manana Subject: Re: [PATCH] Btrfs: fix sleeping inside atomic context in qgroup rescan worker Message-ID: <20151114020350.GE7166@localhost.localdomain> Reply-To: bo.li.liu@oracle.com References: <1446721482-7393-1-git-send-email-fdmanana@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1446721482-7393-1-git-send-email-fdmanana@kernel.org> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, Nov 05, 2015 at 11:04:42AM +0000, fdmanana@kernel.org wrote: > From: Filipe Manana > > We are holding a btree path with spinning locks and then we attempt to > clone an extent buffer, which calls kmem_cache_alloc() and this function > can sleep, causing the following trace to be reported on a debug kernel: > > [107118.218536] BUG: sleeping function called from invalid context at mm/slab.c:2871 > [107118.224110] in_atomic(): 1, irqs_disabled(): 0, pid: 19148, name: kworker/u32:3 > [107118.226120] INFO: lockdep is turned off. > [107118.226843] Preemption disabled at:[] btrfs_clear_lock_blocking_rw+0x96/0xea [btrfs] > > [107118.229175] CPU: 3 PID: 19148 Comm: kworker/u32:3 Tainted: G W 4.3.0-rc5-btrfs-next-17+ #1 > [107118.231326] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014 > [107118.233687] Workqueue: btrfs-qgroup-rescan btrfs_qgroup_rescan_helper [btrfs] > [107118.236835] 0000000000000000 ffff880424bf3b78 ffffffff812566f4 0000000000000000 > [107118.238369] ffff880424bf3ba0 ffffffff81070664 ffffffff817f1cd5 0000000000000b37 > [107118.239769] 0000000000000000 ffff880424bf3bc8 ffffffff8107070a 0000000000008850 > [107118.241244] Call Trace: > [107118.241729] [] dump_stack+0x4e/0x79 > [107118.242602] [] ___might_sleep+0x23a/0x241 > [107118.243586] [] __might_sleep+0x9f/0xa6 > [107118.244532] [] cache_alloc_debugcheck_before+0x25/0x36 > [107118.245939] [] kmem_cache_alloc+0x50/0x215 > [107118.246930] [] __alloc_extent_buffer+0x2a/0x11f [btrfs] > [107118.248121] [] btrfs_clone_extent_buffer+0x3d/0xdd [btrfs] > [107118.249451] [] btrfs_qgroup_rescan_worker+0x16d/0x434 [btrfs] > [107118.250755] [] ? arch_local_irq_save+0x9/0xc > [107118.251754] [] normal_work_helper+0x14c/0x32a [btrfs] > [107118.252899] [] ? normal_work_helper+0x14c/0x32a [btrfs] > [107118.254195] [] btrfs_qgroup_rescan_helper+0x12/0x14 [btrfs] > [107118.255436] [] process_one_work+0x24a/0x4ac > [107118.263690] [] worker_thread+0x206/0x2c2 > [107118.264888] [] ? rescuer_thread+0x2cb/0x2cb > [107118.267413] [] kthread+0xef/0xf7 > [107118.268417] [] ? kthread_parkme+0x24/0x24 > [107118.269505] [] ret_from_fork+0x3f/0x70 > [107118.270491] [] ? kthread_parkme+0x24/0x24 > > So just use blocking locks for our path to solve this. > This fixes the patch titled: > "btrfs: qgroup: Don't copy extent buffer to do qgroup rescan" Reviewed-by: Liu Bo Thanks, -liubo > > Signed-off-by: Filipe Manana > --- > fs/btrfs/qgroup.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c > index 75bb4af9..93e12c1 100644 > --- a/fs/btrfs/qgroup.c > +++ b/fs/btrfs/qgroup.c > @@ -2198,7 +2198,6 @@ qgroup_rescan_leaf(struct btrfs_fs_info *fs_info, struct btrfs_path *path, > int slot; > int ret; > > - path->leave_spinning = 1; > mutex_lock(&fs_info->qgroup_rescan_lock); > ret = btrfs_search_slot_for_read(fs_info->extent_root, > &fs_info->qgroup_rescan_progress, > -- > 2.1.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html