Patch "bcache: prevent crash on changing writeback_running" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

bcache: prevent crash on changing writeback_running

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
bcache-prevent-crash-on-changing-writeback_running.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Stefan Bader <[email protected]>
Date: Sun, 29 Nov 2015 18:44:49 -0800
Subject: bcache: prevent crash on changing writeback_running

From: Stefan Bader <[email protected]>

commit 8d16ce540c94c9d366eb36fc91b7154d92d6397b upstream.

Added a safeguard in the shutdown case. At least while not being attached it is also possible to trigger a kernel bug by writing into writeback_running. This change adds the same check before trying to wake up the thread for that case.

---
 drivers/md/bcache/writeback.h |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -63,7 +63,8 @@ static inline bool should_writeback(stru
 
 static inline void bch_writeback_queue(struct cached_dev *dc)
 {
-	wake_up_process(dc->writeback_thread);
+	if (!IS_ERR_OR_NULL(dc->writeback_thread))
+		wake_up_process(dc->writeback_thread);
 }
 
 static inline void bch_writeback_add(struct cached_dev *dc)

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/bcache-prevent-crash-on-changing-writeback_running.patch