5.4-stable patches

added patches:
	scsi-block-fix-a-race-in-the-runtime-power-management-code.patch

diff --git a/queue-5.4/scsi-block-fix-a-race-in-the-runtime-power-management-code.patch b/queue-5.4/scsi-block-fix-a-race-in-the-runtime-power-management-code.patch
new file mode 100644 (file)
index 0000000..45bd2d8
--- /dev/null
+++ b/queue-5.4/scsi-block-fix-a-race-in-the-runtime-power-management-code.patch
@@ -0,0 +1,80 @@
+From fa4d0f1992a96f6d7c988ef423e3127e613f6ac9 Mon Sep 17 00:00:00 2001
+From: Bart Van Assche <bvanassche@acm.org>
+Date: Tue, 8 Dec 2020 21:29:44 -0800
+Subject: scsi: block: Fix a race in the runtime power management code
+
+From: Bart Van Assche <bvanassche@acm.org>
+
+commit fa4d0f1992a96f6d7c988ef423e3127e613f6ac9 upstream.
+
+With the current implementation the following race can happen:
+
+ * blk_pre_runtime_suspend() calls blk_freeze_queue_start() and
+   blk_mq_unfreeze_queue().
+
+ * blk_queue_enter() calls blk_queue_pm_only() and that function returns
+   true.
+
+ * blk_queue_enter() calls blk_pm_request_resume() and that function does
+   not call pm_request_resume() because the queue runtime status is
+   RPM_ACTIVE.
+
+ * blk_pre_runtime_suspend() changes the queue status into RPM_SUSPENDING.
+
+Fix this race by changing the queue runtime status into RPM_SUSPENDING
+before switching q_usage_counter to atomic mode.
+
+Link: https://lore.kernel.org/r/20201209052951.16136-2-bvanassche@acm.org
+Fixes: 986d413b7c15 ("blk-mq: Enable support for runtime power management")
+Cc: Ming Lei <ming.lei@redhat.com>
+Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+Cc: stable <stable@vger.kernel.org>
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Reviewed-by: Hannes Reinecke <hare@suse.de>
+Reviewed-by: Jens Axboe <axboe@kernel.dk>
+Acked-by: Alan Stern <stern@rowland.harvard.edu>
+Acked-by: Stanley Chu <stanley.chu@mediatek.com>
+Co-developed-by: Can Guo <cang@codeaurora.org>
+Signed-off-by: Can Guo <cang@codeaurora.org>
+Signed-off-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>
+
+---
+ block/blk-pm.c |   15 +++++++++------
+ 1 file changed, 9 insertions(+), 6 deletions(-)
+
+--- a/block/blk-pm.c
++++ b/block/blk-pm.c
+@@ -67,6 +67,10 @@ int blk_pre_runtime_suspend(struct reque
+ 
+       WARN_ON_ONCE(q->rpm_status != RPM_ACTIVE);
+ 
++      spin_lock_irq(&q->queue_lock);
++      q->rpm_status = RPM_SUSPENDING;
++      spin_unlock_irq(&q->queue_lock);
++
+       /*
+        * Increase the pm_only counter before checking whether any
+        * non-PM blk_queue_enter() calls are in progress to avoid that any
+@@ -89,15 +93,14 @@ int blk_pre_runtime_suspend(struct reque
+       /* Switch q_usage_counter back to per-cpu mode. */
+       blk_mq_unfreeze_queue(q);
+ 
+-      spin_lock_irq(&q->queue_lock);
+-      if (ret < 0)
++      if (ret < 0) {
++              spin_lock_irq(&q->queue_lock);
++              q->rpm_status = RPM_ACTIVE;
+               pm_runtime_mark_last_busy(q->dev);
+-      else
+-              q->rpm_status = RPM_SUSPENDING;
+-      spin_unlock_irq(&q->queue_lock);
++              spin_unlock_irq(&q->queue_lock);
+ 
+-      if (ret)
+               blk_clear_pm_only(q);
++      }
+ 
+       return ret;
+ }

diff --git a/queue-5.4/series b/queue-5.4/series
index 019fc59e7affe17857d3708cf925a27d3be37474..510b254a9d95807e522feea8643413904b979039 100644 (file)
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -15,3 +15,4 @@ kvm-x86-reinstate-vendor-agnostic-check-on-spec_ctrl.patch
 powerpc-bitops-fix-possible-undefined-behaviour-with.patch
 jffs2-allow-setting-rp_size-to-zero-during-remountin.patch
 jffs2-fix-null-pointer-dereference-in-rp_size-fs-opt.patch
+scsi-block-fix-a-race-in-the-runtime-power-management-code.patch