4.20-stable review patch. If anyone has any objections, please let me know.
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From: Stanley Chu stanley.chu@mediatek.com
commit 3f7e62bba0003f9c68f599f5997c4647ef5b4f4e upstream.
The commit 356fd2663cff ("scsi: Set request queue runtime PM status back to active on resume") fixed up the inconsistent RPM status between request queue and device. However changing request queue RPM status shall be done only on successful resume, otherwise status may be still inconsistent as below,
Request queue: RPM_ACTIVE Device: RPM_SUSPENDED
This ends up soft lockup because requests can be submitted to underlying devices but those devices and their required resource are not resumed.
For example,
After above inconsistent status happens, IO request can be submitted to UFS device driver but required resource (like clock) is not resumed yet thus lead to warning as below call stack,
WARN_ON(hba->clk_gating.state != CLKS_ON); ufshcd_queuecommand scsi_dispatch_cmd scsi_request_fn __blk_run_queue cfq_insert_request __elv_add_request blk_flush_plug_list blk_finish_plug jbd2_journal_commit_transaction kjournald2
We may see all behind IO requests hang because of no response from storage host or device and then soft lockup happens in system. In the end, system may crash in many ways.
Fixes: 356fd2663cff (scsi: Set request queue runtime PM status back to active on resume) Cc: stable@vger.kernel.org Signed-off-by: Stanley Chu stanley.chu@mediatek.com Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/scsi/scsi_pm.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-)
--- a/drivers/scsi/scsi_pm.c +++ b/drivers/scsi/scsi_pm.c @@ -80,8 +80,22 @@ static int scsi_dev_type_resume(struct d
if (err == 0) { pm_runtime_disable(dev); - pm_runtime_set_active(dev); + err = pm_runtime_set_active(dev); pm_runtime_enable(dev); + + /* + * Forcibly set runtime PM status of request queue to "active" + * to make sure we can again get requests from the queue + * (see also blk_pm_peek_request()). + * + * The resume hook will correct runtime PM status of the disk. + */ + if (!err && scsi_is_sdev_device(dev)) { + struct scsi_device *sdev = to_scsi_device(dev); + + if (sdev->request_queue->dev) + blk_set_runtime_active(sdev->request_queue); + } }
return err; @@ -140,16 +154,6 @@ static int scsi_bus_resume_common(struct else fn = NULL;
- /* - * Forcibly set runtime PM status of request queue to "active" to - * make sure we can again get requests from the queue (see also - * blk_pm_peek_request()). - * - * The resume hook will correct runtime PM status of the disk. - */ - if (scsi_is_sdev_device(dev) && pm_runtime_suspended(dev)) - blk_set_runtime_active(to_scsi_device(dev)->request_queue); - if (fn) { async_schedule_domain(fn, dev, &scsi_sd_pm_domain);