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authorBart Van Assche <bvanassche@acm.org>2014-07-09 15:57:26 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-09-17 09:04:02 -0700
commit70efec16cf060603b54ea71c9cb4499f052efd69 (patch)
treece26214f5ebb52d1115ebf515ce3305c4b7654c0 /drivers/infiniband
parentf5b48b7a3d0d1ab761ba939b6cbb4a07d37a750b (diff)
downloadlinux-linaro-stable-70efec16cf060603b54ea71c9cb4499f052efd69.tar.gz
IB/srp: Fix deadlock between host removal and multipathd
commit bcc05910359183b431da92713e98eed478edf83a upstream. If scsi_remove_host() is invoked after a SCSI device has been blocked, if the fast_io_fail_tmo or dev_loss_tmo work gets scheduled on the workqueue executing srp_remove_work() and if an I/O request is scheduled after the SCSI device had been blocked by e.g. multipathd then the following deadlock can occur: kworker/6:1 D ffff880831f3c460 0 195 2 0x00000000 Call Trace: [<ffffffff814aafd9>] schedule+0x29/0x70 [<ffffffff814aa0ef>] schedule_timeout+0x10f/0x2a0 [<ffffffff8105af6f>] msleep+0x2f/0x40 [<ffffffff8123b0ae>] __blk_drain_queue+0x4e/0x180 [<ffffffff8123d2d5>] blk_cleanup_queue+0x225/0x230 [<ffffffffa0010732>] __scsi_remove_device+0x62/0xe0 [scsi_mod] [<ffffffffa000ed2f>] scsi_forget_host+0x6f/0x80 [scsi_mod] [<ffffffffa0002eba>] scsi_remove_host+0x7a/0x130 [scsi_mod] [<ffffffffa07cf5c5>] srp_remove_work+0x95/0x180 [ib_srp] [<ffffffff8106d7aa>] process_one_work+0x1ea/0x6c0 [<ffffffff8106dd9b>] worker_thread+0x11b/0x3a0 [<ffffffff810758bd>] kthread+0xed/0x110 [<ffffffff814b972c>] ret_from_fork+0x7c/0xb0 multipathd D ffff880096acc460 0 5340 1 0x00000000 Call Trace: [<ffffffff814aafd9>] schedule+0x29/0x70 [<ffffffff814aa0ef>] schedule_timeout+0x10f/0x2a0 [<ffffffff814ab79b>] io_schedule_timeout+0x9b/0xf0 [<ffffffff814abe1c>] wait_for_completion_io_timeout+0xdc/0x110 [<ffffffff81244b9b>] blk_execute_rq+0x9b/0x100 [<ffffffff8124f665>] sg_io+0x1a5/0x450 [<ffffffff8124fd21>] scsi_cmd_ioctl+0x2a1/0x430 [<ffffffff8124fef2>] scsi_cmd_blk_ioctl+0x42/0x50 [<ffffffffa00ec97e>] sd_ioctl+0xbe/0x140 [sd_mod] [<ffffffff8124bd04>] blkdev_ioctl+0x234/0x840 [<ffffffff811cb491>] block_ioctl+0x41/0x50 [<ffffffff811a0df0>] do_vfs_ioctl+0x300/0x520 [<ffffffff811a1051>] SyS_ioctl+0x41/0x80 [<ffffffff814b9962>] tracesys+0xd0/0xd5 Fix this by scheduling removal work on another workqueue than the transport layer timers. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Reviewed-by: David Dillow <dave@thedillows.org> Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com> Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/ulp/srp/ib_srp.c38
1 files changed, 28 insertions, 10 deletions
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 1954daac0b59..35dd5ff662f1 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -93,6 +93,7 @@ static void srp_send_completion(struct ib_cq *cq, void *target_ptr);
static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event);
static struct scsi_transport_template *ib_srp_transport_template;
+static struct workqueue_struct *srp_remove_wq;
static struct ib_client srp_client = {
.name = "srp",
@@ -456,7 +457,7 @@ static bool srp_queue_remove_work(struct srp_target_port *target)
spin_unlock_irq(&target->lock);
if (changed)
- queue_work(system_long_wq, &target->remove_work);
+ queue_work(srp_remove_wq, &target->remove_work);
return changed;
}
@@ -2530,9 +2531,10 @@ static void srp_remove_one(struct ib_device *device)
spin_unlock(&host->target_lock);
/*
- * Wait for target port removal tasks.
+ * Wait for tl_err and target port removal tasks.
*/
flush_workqueue(system_long_wq);
+ flush_workqueue(srp_remove_wq);
kfree(host);
}
@@ -2577,16 +2579,22 @@ static int __init srp_init_module(void)
indirect_sg_entries = cmd_sg_entries;
}
+ srp_remove_wq = create_workqueue("srp_remove");
+ if (IS_ERR(srp_remove_wq)) {
+ ret = PTR_ERR(srp_remove_wq);
+ goto out;
+ }
+
+ ret = -ENOMEM;
ib_srp_transport_template =
srp_attach_transport(&ib_srp_transport_functions);
if (!ib_srp_transport_template)
- return -ENOMEM;
+ goto destroy_wq;
ret = class_register(&srp_class);
if (ret) {
pr_err("couldn't register class infiniband_srp\n");
- srp_release_transport(ib_srp_transport_template);
- return ret;
+ goto release_tr;
}
ib_sa_register_client(&srp_sa_client);
@@ -2594,13 +2602,22 @@ static int __init srp_init_module(void)
ret = ib_register_client(&srp_client);
if (ret) {
pr_err("couldn't register IB client\n");
- srp_release_transport(ib_srp_transport_template);
- ib_sa_unregister_client(&srp_sa_client);
- class_unregister(&srp_class);
- return ret;
+ goto unreg_sa;
}
- return 0;
+out:
+ return ret;
+
+unreg_sa:
+ ib_sa_unregister_client(&srp_sa_client);
+ class_unregister(&srp_class);
+
+release_tr:
+ srp_release_transport(ib_srp_transport_template);
+
+destroy_wq:
+ destroy_workqueue(srp_remove_wq);
+ goto out;
}
static void __exit srp_cleanup_module(void)
@@ -2609,6 +2626,7 @@ static void __exit srp_cleanup_module(void)
ib_sa_unregister_client(&srp_sa_client);
class_unregister(&srp_class);
srp_release_transport(ib_srp_transport_template);
+ destroy_workqueue(srp_remove_wq);
}
module_init(srp_init_module);