Bean Huo 99c66a8868 scsi: ufs: core: Fix deadlock issue in ufshcd_wait_for_doorbell_clr()
Call shost_for_each_device() with holding host->host_lock will cause a
deadlock situation, which will cause the system to stall (the log as
follow). Fix this issue by using __shost_for_each_device() in
ufshcd_pending_cmds().

stalls on CPUs/tasks:
all trace:
__switch_to+0x120/0x170
0xffff800011643998
ask dump for CPU 5:
ask:kworker/u16:2   state:R  running task     stack:    0 pid:   80 ppid:     2 flags:0x0000000a
orkqueue: events_unbound async_run_entry_fn
all trace:
__switch_to+0x120/0x170
0x0
ask dump for CPU 6:
ask:kworker/u16:6   state:R  running task     stack:    0 pid:  164 ppid:     2 flags:0x0000000a
orkqueue: events_unbound async_run_entry_fn
all trace:
__switch_to+0x120/0x170
0xffff54e7c4429f80
ask dump for CPU 7:
ask:kworker/u16:4   state:R  running task     stack:    0 pid:  153 ppid:     2 flags:0x0000000a
orkqueue: events_unbound async_run_entry_fn
all trace:
__switch_to+0x120/0x170
blk_mq_run_hw_queue+0x34/0x110
blk_mq_sched_insert_request+0xb0/0x120
blk_execute_rq_nowait+0x68/0x88
blk_execute_rq+0x4c/0xd8
__scsi_execute+0xec/0x1d0
scsi_vpd_inquiry+0x84/0xf0
scsi_get_vpd_buf+0x34/0xb8
scsi_attach_vpd+0x34/0x140
scsi_probe_and_add_lun+0xa6c/0xab8
__scsi_scan_target+0x438/0x4f8
scsi_scan_channel+0x6c/0xa8
scsi_scan_host_selected+0xf0/0x150
do_scsi_scan_host+0x88/0x90
scsi_scan_host+0x1b4/0x1d0
ufshcd_async_scan+0x248/0x310
async_run_entry_fn+0x30/0x178
process_one_work+0x1e8/0x368
worker_thread+0x40/0x478
kthread+0x174/0x180
ret_from_fork+0x10/0x20

Link: https://lore.kernel.org/r/20211214120537.531628-1-huobean@gmail.com
Fixes: 8d077ede48c1 ("scsi: ufs: Optimize the command queueing code")
Reported-by: YongQin Liu <yongqin.liu@linaro.org>
Reported-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Co-developed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-12-16 22:51:13 -05:00
2021-11-13 15:32:30 -08:00
2021-11-14 12:18:22 -08:00
2021-11-13 15:32:30 -08:00
2021-11-13 10:45:17 -08:00
2021-11-12 12:17:30 -08:00
2021-12-06 22:19:32 -05:00
2021-11-14 13:56:52 -08:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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