From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757399Ab3E1VVn (ORCPT ); Tue, 28 May 2013 17:21:43 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:59556 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757188Ab3E1VVY (ORCPT ); Tue, 28 May 2013 17:21:24 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Jun'ichi Nomura" , Alasdair G Kergon , Jens Axboe , Kamal Mostafa Subject: [PATCH 04/78] blkcg: fix "scheduling while atomic" in blk_queue_bypass_start Date: Tue, 28 May 2013 14:19:13 -0700 Message-Id: <1369776027-17859-5-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1369776027-17859-1-git-send-email-kamal@canonical.com> References: <1369776027-17859-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.8.13.1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jun'ichi Nomura commit e5072664f8237cf53b0bd68a51aa1a7bc69061c5 upstream. Since 749fefe677 in v3.7 ("block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue()"), the following warning appears when multipath is used with CONFIG_PREEMPT=y. This patch moves blk_queue_bypass_start() before radix_tree_preload() to avoid the sleeping call while preemption is disabled. BUG: scheduling while atomic: multipath/2460/0x00000002 1 lock held by multipath/2460: #0: (&md->type_lock){......}, at: [] dm_lock_md_type+0x17/0x19 [dm_mod] Modules linked in: ... Pid: 2460, comm: multipath Tainted: G W 3.7.0-rc2 #1 Call Trace: [] __schedule_bug+0x6a/0x78 [] __schedule+0xb4/0x5e0 [] schedule+0x64/0x66 [] schedule_timeout+0x39/0xf8 [] ? put_lock_stats+0xe/0x29 [] ? lock_release_holdtime+0xb6/0xbb [] wait_for_common+0x9d/0xee [] ? try_to_wake_up+0x206/0x206 [] ? kfree_call_rcu+0x1c/0x1c [] wait_for_completion+0x1d/0x1f [] wait_rcu_gp+0x5d/0x7a [] ? wait_rcu_gp+0x7a/0x7a [] ? complete+0x21/0x53 [] synchronize_rcu+0x1e/0x20 [] blk_queue_bypass_start+0x5d/0x62 [] blkcg_activate_policy+0x73/0x270 [] ? kmem_cache_alloc_node_trace+0xc7/0x108 [] cfq_init_queue+0x80/0x28e [] ? dm_blk_ioctl+0xa7/0xa7 [dm_mod] [] elevator_init+0xe1/0x115 [] ? blk_queue_make_request+0x54/0x59 [] blk_init_allocated_queue+0x8c/0x9e [] dm_setup_md_queue+0x36/0xaa [dm_mod] [] table_load+0x1bd/0x2c8 [dm_mod] [] ctl_ioctl+0x1d6/0x236 [dm_mod] [] ? table_clear+0xaa/0xaa [dm_mod] [] dm_ctl_ioctl+0x13/0x17 [dm_mod] [] do_vfs_ioctl+0x3fb/0x441 [] ? file_has_perm+0x8a/0x99 [] sys_ioctl+0x5e/0x82 [] ? trace_hardirqs_on_thunk+0x3a/0x3f [] system_call_fastpath+0x16/0x1b Signed-off-by: Jun'ichi Nomura Acked-by: Vivek Goyal Acked-by: Tejun Heo Cc: Alasdair G Kergon Signed-off-by: Jens Axboe [ Jun'ichi: backport to 3.8 ] Signed-off-by: Kamal Mostafa --- block/blk-cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index b8858fb..53628e4 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -790,10 +790,10 @@ int blkcg_activate_policy(struct request_queue *q, if (!blkg) return -ENOMEM; - preloaded = !radix_tree_preload(GFP_KERNEL); - blk_queue_bypass_start(q); + preloaded = !radix_tree_preload(GFP_KERNEL); + /* make sure the root blkg exists and count the existing blkgs */ spin_lock_irq(q->queue_lock); -- 1.8.1.2