summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--drivers/ata/libata-scsi.c21
-rw-r--r--kernel/freezer.c6
2 files changed, 27 insertions, 0 deletions
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index db6dfcfa3e2e..176f62950e3d 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3871,6 +3871,27 @@ 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);
diff --git a/kernel/freezer.c b/kernel/freezer.c
index b462fa197517..aa6a8aadb911 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -19,6 +19,12 @@ EXPORT_SYMBOL(system_freezing_cnt);
bool pm_freezing;
bool pm_nosig_freezing;
+/*
+ * Temporary export for the deadlock workaround in ata_scsi_hotplug().
+ * Remove once the hack becomes unnecessary.
+ */
+EXPORT_SYMBOL_GPL(pm_freezing);
+
/* protects freezing and frozen transitions */
static DEFINE_SPINLOCK(freezer_lock);