block: fix deadlock between sd_remove & sd_release

In the Linux kernel, the following vulnerability has been resolved:

block: fix deadlock between sd_remove & sd_release

Our test report the following hung task:

[ 2538.459400] INFO: task "kworker/0:0":7 blocked for more than 188 seconds.

[ 2538.459427] Call trace:

[ 2538.459430] __switch_to+0x174/0x338

[ 2538.459436] __schedule+0x628/0x9c4

[ 2538.459442] schedule+0x7c/0xe8

[ 2538.459447] schedule_preempt_disabled+0x24/0x40

[ 2538.459453] __mutex_lock+0x3ec/0xf04

[ 2538.459456] __mutex_lock_slowpath+0x14/0x24

[ 2538.459459] mutex_lock+0x30/0xd8

[ 2538.459462] del_gendisk+0xdc/0x350

[ 2538.459466] sd_remove+0x30/0x60

[ 2538.459470] device_release_driver_internal+0x1c4/0x2c4

[ 2538.459474] device_release_driver+0x18/0x28

[ 2538.459478] bus_remove_device+0x15c/0x174

[ 2538.459483] device_del+0x1d0/0x358

[ 2538.459488] __scsi_remove_device+0xa8/0x198

[ 2538.459493] scsi_forget_host+0x50/0x70

[ 2538.459497] scsi_remove_host+0x80/0x180

[ 2538.459502] usb_stor_disconnect+0x68/0xf4

[ 2538.459506] usb_unbind_interface+0xd4/0x280

[ 2538.459510] device_release_driver_internal+0x1c4/0x2c4

[ 2538.459514] device_release_driver+0x18/0x28

[ 2538.459518] bus_remove_device+0x15c/0x174

[ 2538.459523] device_del+0x1d0/0x358

[ 2538.459528] usb_disable_device+0x84/0x194

[ 2538.459532] usb_disconnect+0xec/0x300

[ 2538.459537] hub_event+0xb80/0x1870

[ 2538.459541] process_scheduled_works+0x248/0x4dc

[ 2538.459545] worker_thread+0x244/0x334

[ 2538.459549] kthread+0x114/0x1bc

[ 2538.461001] INFO: task "fsck.":15415 blocked for more than 188 seconds.

[ 2538.461014] Call trace:

[ 2538.461016] __switch_to+0x174/0x338

[ 2538.461021] __schedule+0x628/0x9c4

[ 2538.461025] schedule+0x7c/0xe8

[ 2538.461030] blk_queue_enter+0xc4/0x160

[ 2538.461034] blk_mq_alloc_request+0x120/0x1d4

[ 2538.461037] scsi_execute_cmd+0x7c/0x23c

[ 2538.461040] ioctl_internal_command+0x5c/0x164

[ 2538.461046] scsi_set_medium_removal+0x5c/0xb0

[ 2538.461051] sd_release+0x50/0x94

[ 2538.461054] blkdev_put+0x190/0x28c

[ 2538.461058] blkdev_release+0x28/0x40

[ 2538.461063] __fput+0xf8/0x2a8

[ 2538.461066] __fput_sync+0x28/0x5c

[ 2538.461070] __arm64_sys_close+0x84/0xe8

[ 2538.461073] invoke_syscall+0x58/0x114

[ 2538.461078] el0_svc_common+0xac/0xe0

[ 2538.461082] do_el0_svc+0x1c/0x28

[ 2538.461087] el0_svc+0x38/0x68

[ 2538.461090] el0t_64_sync_handler+0x68/0xbc

[ 2538.461093] el0t_64_sync+0x1a8/0x1ac

T1: T2:

sd_remove

del_gendisk

__blk_mark_disk_dead

blk_freeze_queue_start

++q->mq_freeze_depth

bdev_release

mutex_lock(&disk->open_mutex)

sd_release

scsi_execute_cmd

blk_queue_enter

wait_event(!q->mq_freeze_depth)

mutex_lock(&disk->open_mutex)

SCSI does not set GD_OWNS_QUEUE, so QUEUE_FLAG_DYING is not set in

this scenario. This is a classic ABBA deadlock. To fix the deadlock,

make sure we don't try to acquire disk->open_mutex after freezing

the queue.