在 2017/11/2 20:16, Zouming (IT) 写道:
1.Repeat steps:
(1) send IO on the device /dev/sdx.
(2) Simulate an IO lost
(3) Use the command before to delete scsi device before IO timeout
ehco 1 > /sys/class/sdx/device/delete
2.The stack of delete thead is before:
[<ffffffff810999ef>] msleep+0x2f/0x40
[<ffffffff812f78b4>] __blk_drain_queue+0xa4/0x170
[<ffffffff812f7bfd>] blk_cleanup_queue+0x13d/0x150
[<ffffffff81473d2a>] __scsi_remove_device+0x4a/0xd0
[<ffffffff81473dd6>] scsi_remove_device+0x26/0x40
[<ffffffff81473e05>] sdev_store_delete_callback+0x15/0x20
[<ffffffff8127fdc4>] sysfs_schedule_callback_work+0x14/0x60
[<ffffffff810a881a>] process_one_work+0x17a/0x440
[<ffffffff810a94e6>] worker_thread+0x126/0x3c0
[<ffffffff810b098f>] kthread+0xcf/0xe0
[<ffffffff816b4f18>] ret_from_fork+0x58/0x90
3.The reason is before:
(1) When the scsi device is deleted, invoke blk_cleanup_queue funtion to
set the flag of request_queue dying, and wait all IO back.
(2) when IO timout,the timeout workqueue invoke blk_timeout_work function to abort IO,
but it will not abort the IO because it call blk_queue_enter funtion
judge the request_queue is dying and return direct without doing anything.
Hi Zouming,
You can have a test on Bart's patch "[PATCH] block: Fix a race between
blk_cleanup_queue() and timeout handling" for this issue.
I think this patch can solve your issue.
