Bart Van Assche 7029e2151a scsi: ufs: Fix a deadlock between PM and the SCSI error handler ... The following deadlock has been observed on multiple test setups: * ufshcd_wl_suspend() is waiting for blk_execute_rq(START STOP UNIT) to complete while ufshcd_wl_suspend() holds host_sem. * The SCSI error handler is activated, changes the host state to SHOST_RECOVERY, ufshcd_eh_host_reset_handler() and ufshcd_err_handler() are called and the latter function tries to obtain host_sem. This is a deadlock because blk_execute_rq() can't execute SCSI commands while the host is in the SHOST_RECOVERY state and because the error handler cannot make progress because host_sem is held by another thread. Fix this deadlock as follows: * Fail attempts to suspend the system while the SCSI error handler is in progress by setting the SCMD_FAIL_IF_RECOVERING flag for START STOP UNIT commands. * If the system is suspending and a START STOP UNIT command times out, handle the SCSI command timeout from inside the context of the SCSI timeout handler instead of activating the SCSI error handler. The runtime power management code is not affected by this deadlock since hba->host_sem is not touched by the runtime power management functions in the UFS driver. Reviewed-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20221018202958.1902564-11-bvanassche@acm.org Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>		2022-10-22 03:26:00 +00:00
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core	scsi: ufs: Fix a deadlock between PM and the SCSI error handler	2022-10-22 03:26:00 +00:00
host	SCSI misc on 20221007	2022-10-07 12:33:18 -07:00
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