3.10-stable patches

added patches:
	scsi-fix-scsi_error_handler-vs.-scsi_host_dev_release-race.patch

diff --git a/queue-3.10/scsi-fix-scsi_error_handler-vs.-scsi_host_dev_release-race.patch b/queue-3.10/scsi-fix-scsi_error_handler-vs.-scsi_host_dev_release-race.patch
new file mode 100644 (file)
index 0000000..85ff93a
--- /dev/null
+++ b/queue-3.10/scsi-fix-scsi_error_handler-vs.-scsi_host_dev_release-race.patch
@@ -0,0 +1,65 @@
+From 537b604c8b3aa8b96fe35f87dd085816552e294c Mon Sep 17 00:00:00 2001
+From: Michal Hocko <mhocko@suse.com>
+Date: Thu, 27 Aug 2015 20:16:37 +0200
+Subject: scsi: fix scsi_error_handler vs. scsi_host_dev_release race
+
+From: Michal Hocko <mhocko@suse.com>
+
+commit 537b604c8b3aa8b96fe35f87dd085816552e294c upstream.
+
+b9d5c6b7ef57 ("[SCSI] cleanup setting task state in
+scsi_error_handler()") has introduced a race between scsi_error_handler
+and scsi_host_dev_release resulting in the hang when the device goes
+away because scsi_error_handler might miss a wake up:
+
+CPU0                                   CPU1
+scsi_error_handler                     scsi_host_dev_release
+                                         kthread_stop()
+  kthread_should_stop()
+    test_bit(KTHREAD_SHOULD_STOP)
+                                           set_bit(KTHREAD_SHOULD_STOP)
+                                           wake_up_process()
+                                           wait_for_completion()
+
+  set_current_state(TASK_INTERRUPTIBLE)
+  schedule()
+
+The most straightforward solution seems to be to invert the ordering of
+the set_current_state and kthread_should_stop.
+
+The issue has been noticed during reboot test on a 3.0 based kernel but
+the current code seems to be affected in the same way.
+
+[jejb: additional comment added]
+Reported-and-debugged-by: Mike Mayer <Mike.Meyer@teradata.com>
+Signed-off-by: Michal Hocko <mhocko@suse.com>
+Reviewed-by: Dan Williams <dan.j.williams@intel.com>
+Reviewed-by: Hannes Reinecke <hare@suse.de>
+Signed-off-by: James Bottomley <JBottomley@Odin.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/scsi/scsi_error.c |   11 ++++++++++-
+ 1 file changed, 10 insertions(+), 1 deletion(-)
+
+--- a/drivers/scsi/scsi_error.c
++++ b/drivers/scsi/scsi_error.c
+@@ -1849,8 +1849,17 @@ int scsi_error_handler(void *data)
+        * We never actually get interrupted because kthread_run
+        * disables signal delivery for the created thread.
+        */
+-      while (!kthread_should_stop()) {
++      while (true) {
++              /*
++               * The sequence in kthread_stop() sets the stop flag first
++               * then wakes the process.  To avoid missed wakeups, the task
++               * should always be in a non running state before the stop
++               * flag is checked
++               */
+               set_current_state(TASK_INTERRUPTIBLE);
++              if (kthread_should_stop())
++                      break;
++
+               if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
+                   shost->host_failed != shost->host_busy) {
+                       SCSI_LOG_ERROR_RECOVERY(1,

diff --git a/queue-3.10/series b/queue-3.10/series
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..339dd086877c10d73fb364dd83267c3b473006da 100644 (file)
--- a/queue-3.10/series
+++ b/queue-3.10/series
@@ -0,0 +1 @@
+scsi-fix-scsi_error_handler-vs.-scsi_host_dev_release-race.patch