Merge branch 'perf/urgent' into perf/core

Pick up the latest fixes, refresh the development tree.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index ab58556..377eb88 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3872,6 +3872,27 @@ void ata_scsi_hotplug(struct work_struct *work)
 		return;
 	}
 
+	/*
+	 * XXX - UGLY HACK
+	 *
+	 * The block layer suspend/resume path is fundamentally broken due
+	 * to freezable kthreads and workqueue and may deadlock if a block
+	 * device gets removed while resume is in progress.  I don't know
+	 * what the solution is short of removing freezable kthreads and
+	 * workqueues altogether.
+	 *
+	 * The following is an ugly hack to avoid kicking off device
+	 * removal while freezer is active.  This is a joke but does avoid
+	 * this particular deadlock scenario.
+	 *
+	 * https://bugzilla.kernel.org/show_bug.cgi?id=62801
+	 * http://marc.info/?l=linux-kernel&m=138695698516487
+	 */
+#ifdef CONFIG_FREEZER
+	while (pm_freezing)
+		msleep(10);
+#endif
+
 	DPRINTK("ENTER\n");
 	mutex_lock(&ap->scsi_scan_mutex);