Hi, (adding James)
On Wed, 4 Oct 2023 17:58:03 +0900
Damien Le Moal <dlemoal@xxxxxxxxxx> wrote:
> Commit ff48b37802e5 ("scsi: Do not attempt to rescan suspended devices")
> modified scsi_rescan_device() to avoid attempting rescanning a suspended
> device. However, the modification added a check to verify that a SCSI
> device is in the running state without checking if the device request
> queue (in the case of block device) is also running, thus allowing the
> exectuion of internal requests. Without checking the device request
> queue, commit ff48b37802e5 fix is incomplete and deadlocks on resume can
> still happen. Use blk_queue_pm_only() to check if the device request
> queue allows executing commands in addition to checking the SCSI device
> state.
FTR this fix is still needed for rc5. Is there any chance it goes into
fixes before v6.6 is final?
Petr T
> Reported-by: Petr Tesarik <petr@xxxxxxxxxxx>
> Fixes: ff48b37802e5 ("scsi: Do not attempt to rescan suspended
> devices") Cc: stable@xxxxxxxxxxxxxxx
> Tested-by: Petr Tesarik <petr@xxxxxxxxxxx>
> Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
> ---
> drivers/scsi/scsi_scan.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 3db4d31a03a1..b05a55f498a2 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -1627,12 +1627,13 @@ int scsi_rescan_device(struct scsi_device
> *sdev) device_lock(dev);
>
> /*
> - * Bail out if the device is not running. Otherwise, the
> rescan may
> - * block waiting for commands to be executed, with us
> holding the
> - * device lock. This can result in a potential deadlock in
> the power
> - * management core code when system resume is on-going.
> + * Bail out if the device or its queue are not running.
> Otherwise,
> + * the rescan may block waiting for commands to be executed,
> with us
> + * holding the device lock. This can result in a potential
> deadlock
> + * in the power management core code when system resume is
> on-going. */
> - if (sdev->sdev_state != SDEV_RUNNING) {
> + if (sdev->sdev_state != SDEV_RUNNING ||
> + blk_queue_pm_only(sdev->request_queue)) {
> ret = -EWOULDBLOCK;
> goto unlock;
> }
