When trying to remove a megaraid_sas device, the scst will hang inside

mirror of https://github.com/SCST-project/scst.git synced 2026-08-20 06:06:23 +00:00

scst_free_device:

[  380.448608] [4]: scst: Detached from scsi0, channel 2, id 1, lun 0, type 0
[  601.138688] INFO: task kworker/0:0:4 blocked for more than 120 seconds.
[  601.138756]       Tainted: P           OE  3.19.0-58-quantastor #64~14.04.1
[  601.138810] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  601.138869] kworker/0:0     D ffff88085c6fba58     0     4      2 0x00000000
[  601.138926] Workqueue: events megasas_aen_polling [megaraid_sas]
[  601.138930]  ffff88085c6fba58 ffff88085c6f09d0 0000000000013e80 ffff88085c6fbfd8
[  601.138934]  0000000000013e80 ffffffff81c1d4e0 ffff88085c6f09d0 ffff88085c6fba38
[  601.138938]  ffff88085c6fbbd8 7fffffffffffffff ffff88085c6fbbd0 ffff88085c6f09d0
[  601.138942] Call Trace:
[  601.138955]  [<ffffffff817b5469>] schedule+0x29/0x70
[  601.138960]  [<ffffffff817b8574>] schedule_timeout+0x244/0x2c0
[  601.138968]  [<ffffffff8115fbcb>] ? irq_work_queue+0x6b/0x90
[  601.138975]  [<ffffffff810cb8e2>] ? wake_up_klogd+0x32/0x40
[  601.138979]  [<ffffffff810cbaf8>] ? console_unlock+0x208/0x480
[  601.138983]  [<ffffffff817b61c4>] wait_for_completion+0xa4/0x170
[  601.138989]  [<ffffffff810a1ea0>] ? wake_up_state+0x20/0x20
[  601.138995]  [<ffffffff8108d94c>] flush_workqueue+0x10c/0x5b0
[  601.139002]  [<ffffffff8108de05>] flush_scheduled_work+0x15/0x20
[  601.139044]  [<ffffffffc09314f6>] scst_free_device+0x16/0x50 [scst]
[  601.139051]  [<ffffffffc091a86f>] scst_remove+0x2df/0x3a0 [scst]
[  601.139056]  [<ffffffffc028c093>] ? enclosure_find+0x93/0xa0 [enclosure]
[  601.139061]  [<ffffffff814f3971>] device_del+0xe1/0x270
[  601.139062]  [<ffffffff814f3b22>] device_unregister+0x22/0x70
[  601.139066]  [<ffffffff815549ab>] __scsi_remove_device+0xbb/0xd0
[  601.139068]  [<ffffffff815549e6>] scsi_remove_device+0x26/0x40
[  601.139074]  [<ffffffffc039fb22>] megasas_aen_polling+0x362/0x610 [megaraid_sas]
[  601.139076]  [<ffffffff8108eeaf>] process_one_work+0x14f/0x440
[  601.139077]  [<ffffffff8108fab8>] worker_thread+0x118/0x510
[  601.139079]  [<ffffffff8108f9a0>] ? rescuer_thread+0x3d0/0x3d0
[  601.139082]  [<ffffffff81094b49>] kthread+0xc9/0xe0
[  601.139084]  [<ffffffff81094a80>] ? kthread_create_on_node+0x1c0/0x1c0
[  601.139087]  [<ffffffff817b9798>] ret_from_fork+0x58/0x90
[  601.139089]  [<ffffffff81094a80>] ? kthread_create_on_node+0x1c0/0x1c0

The problem is that scst_free_device will call flush_scheduled_work to wait
for ext_blockers_work, but scst_free_device itself is called from
schedule_work, thus creating deadlock.

Instead of using heavy-handed flush_scheduled_work, we use flush_work to wait
for ext_blockers_work to finish.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>



git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@6883 d57e44dd-8a1f-0410-8b47-8ef2f437770f

This commit is contained in:

Vladislav Bolkhovitin

2016-05-04 02:43:06 +00:00

parent 5f59850096

commit 33627cc8d8

1 changed files with 1 additions and 1 deletions

									
										scst/src/scst_lib.c
									
		+1
		-1
	
												View File
												
				@@ -4206,7 +4206,7 @@ void scst_free_device(struct scst_device *dev)

				#endif

					/* Ensure that ext_blockers_work is done */

					flush_scheduled_work();

					flush_work(&dev->ext_blockers_work);

					scst_deinit_threads(&dev->dev_cmd_threads);