Patch "btrfs: async-thread: Fix a use-after-free error for trace" has been added to the 4.4-stable tree

Patch "btrfs: async-thread: Fix a use-after-free error for trace" has been added to the 4.4-stable tree

[gregkh]

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

    btrfs: async-thread: Fix a use-after-free error for trace

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:
     btrfs-async-thread-fix-a-use-after-free-error-for-trace.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 <stable@vger.kernel.org> know about it.


>From 0a95b851370b84a4b9d92ee6d1fa0926901d0454 Mon Sep 17 00:00:00 2001
From: Qu Wenruo <quwenruo@cn.fujitsu.com>
Date: Fri, 22 Jan 2016 09:28:38 +0800
Subject: btrfs: async-thread: Fix a use-after-free error for trace

From: Qu Wenruo <quwenruo@cn.fujitsu.com>

commit 0a95b851370b84a4b9d92ee6d1fa0926901d0454 upstream.

Parameter of trace_btrfs_work_queued() can be freed in its workqueue.
So no one use use that pointer after queue_work().

Fix the user-after-free bug by move the trace line before queue_work().

Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/btrfs/async-thread.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -328,8 +328,8 @@ static inline void __btrfs_queue_work(st
 		list_add_tail(&work->ordered_list, &wq->ordered_list);
 		spin_unlock_irqrestore(&wq->list_lock, flags);
 	}
-	queue_work(wq->normal_wq, &work->normal_work);
 	trace_btrfs_work_queued(work);
+	queue_work(wq->normal_wq, &work->normal_work);
 }
 
 void btrfs_queue_work(struct btrfs_workqueue *wq,


Patches currently in stable-queue which might be from quwenruo@cn.fujitsu.com are

queue-4.4/btrfs-async-thread-fix-a-use-after-free-error-for-trace.patch