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872f486259
shost->eh_noresume is currently consulted twice in one error handling
iteration: once before scsi_autopm_get_host() and once again before
scsi_autopm_put_host().
That is racy when a PM-triggered error path flips shost->eh_noresume
while the SCSI EH thread is still running.
The problem flow looks like this:
PM path
ufshcd_set_dev_pwr_mode()
shost->eh_noresume = 1
ufshcd_execute_start_stop <-- trigger EH
...
shost->eh_noresume = 0
EH path
scsi_error_handler()
if (!shost->eh_noresume)
scsi_autopm_get_host() <-- skipped
...
if (!shost->eh_noresume)
scsi_autopm_put_host() <-- executed later
In that case one EH iteration can skip autoresume on entry and still
drop a runtime PM reference on exit. That leaves an unmatched runtime PM
put and can trigger a runtime PM usage count underflow.
Fix this by making eh_noresume a regular bool so it can be accessed with
READ_ONCE() and WRITE_ONCE(). Snapshot it once per EH iteration and use
that snapshot for both runtime PM get and put decisions.
Fixes: ae0751ffc7 ("[SCSI] add flag to skip the runtime PM calls on the host")
Signed-off-by: Hongjie Fang <hongjiefang@asrmicro.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Link: https://patch.msgid.link/20260729111614.2407559-1-hongjiefang@asrmicro.com
Signed-off-by: Martin K. Petersen (Oracle) <mkp@kernel.org>