On 9/22/23 17:29, Damien Le Moal wrote:
scsi_rescan_device() takes a scsi device lock before executing a device handler and device driver rescan methods. Waiting for the completion of any command issued to the device by these methods will thus be done with the device lock held. As a result, there is a risk of deadlocking within the power management code if scsi_rescan_device() is called to handle a device resume with the associated scsi device not yet resumed. Avoid such situation by checking that the target scsi device is in the running state, that is, fully capable of executing commands, before proceeding with the rescan and bailout returning -EWOULDBLOCK otherwise. With this error return, the caller can retry rescaning the device after a delay. The state check is done with the device lock held and is thus safe against incoming suspend power management operations.
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>