From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754954Ab2HaUBN (ORCPT ); Fri, 31 Aug 2012 16:01:13 -0400 Received: from mail-bk0-f46.google.com ([209.85.214.46]:65089 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754922Ab2HaUBH (ORCPT ); Fri, 31 Aug 2012 16:01:07 -0400 From: dongsu.park@profitbricks.com To: bvanassche@acm.org Cc: dillowda@ornl.gov, roland@kernel.org, sean.hefty@intel.com, hal.rosenstock@gmail.com, JBottomley@parallels.com, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Dongsu Park Subject: [PATCH 3/5] ib_srp: hold a mutex when adding a new target port Date: Fri, 31 Aug 2012 22:00:39 +0200 Message-Id: <1346443241-24844-4-git-send-email-dongsu.park@profitbricks.com> X-Mailer: git-send-email 1.7.11.1 In-Reply-To: <1346443241-24844-1-git-send-email-dongsu.park@profitbricks.com> References: <1346443241-24844-1-git-send-email-dongsu.park@profitbricks.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dongsu Park Unter circumstances, srp_rport_add() can make conflicts with srp_rport_delete(), dumping the call trace written below. That does not always occur. But its possible reason is adding sysfs entries for the SRP target too fast, even before the deletion hasn't finished yet. The possible solution is therefore holding a scan_mutex when calling device_add(). Example call trace: ------------[ cut here ]------------ WARNING: at block/genhd.c:1466 __disk_unblock_events+0x10f/0x120() Pid: 17238, comm: scsi_id Not tainted 3.2.8-pserver #1 Call Trace: [] ? warn_slowpath_common+0x7b/0xc0 [] ? __disk_unblock_events+0x10f/0x120 [] ? __blkdev_get+0x190/0x410 [] ? blkdev_get+0x310/0x310 [] ? blkdev_get+0x4b/0x310 [] ? blkdev_get+0x310/0x310 [] ? __dentry_open+0x263/0x370 [] ? path_get+0x1e/0x30 [] ? do_last+0x3e0/0x800 [] ? path_openat+0xdb/0x400 [] ? do_filp_open+0x4d/0xc0 [] ? alloc_fd+0x43/0x130 [] ? do_sys_open+0x105/0x1e0 [] ? system_call_fastpath+0x16/0x1b ---[ end trace 4edc2747f936431c ]--- ------------[ cut here ]------------ WARNING: at fs/sysfs/inode.c:323 sysfs_hash_and_remove+0xa4/0xb0() Hardware name: H8DGU sysfs: can not remove 'bsg', no directory Pid: 15816, comm: kworker/4:8 Tainted: G W 3.2.8 #1 Call Trace: [] ? warn_slowpath_common+0x7b/0xc0 [] ? warn_slowpath_fmt+0x45/0x50 [] ? sysfs_hash_and_remove+0xa4/0xb0 [] ? bsg_unregister_queue+0x3f/0x80 [] ? __scsi_remove_device+0x99/0xc0 [scsi_mod] [] ? scsi_forget_host+0x64/0x70 [scsi_mod] [] ? scsi_remove_host+0x61/0x100 [scsi_mod] [] ? srp_remove_work+0x137/0x1c0 [ib_srp] [] ? srp_free_req_data+0xd0/0xd0 [ib_srp] [] ? process_one_work+0x113/0x470 [] ? manage_workers+0x180/0x200 [] ? worker_thread+0x163/0x3e0 [] ? manage_workers+0x200/0x200 [] ? manage_workers+0x200/0x200 [] ? kthread+0x96/0xa0 [] ? kernel_thread_helper+0x4/0x10 [] ? kthread_worker_fn+0x180/0x180 [] ? gs_change+0x13/0x13 ---[ end trace 4edc2747f936431d ]--- ------------[ cut here ]------------ Signed-off-by: Dongsu Park --- drivers/scsi/scsi_transport_srp.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c index 7f17686..af3cb56 100644 --- a/drivers/scsi/scsi_transport_srp.c +++ b/drivers/scsi/scsi_transport_srp.c @@ -407,12 +407,15 @@ struct srp_rport *srp_rport_add(struct Scsi_Host *shost, transport_setup_device(&rport->dev); + mutex_lock(&shost->scan_mutex); ret = device_add(&rport->dev); if (ret) { + mutex_unlock(&shost->scan_mutex); transport_destroy_device(&rport->dev); put_device(&rport->dev); return ERR_PTR(ret); } + mutex_unlock(&shost->scan_mutex); if (shost->active_mode & MODE_TARGET && ids->roles == SRP_RPORT_ROLE_INITIATOR) { -- 1.7.11.1