Hi

Please apply this before 3.19 is released.

Mikulas


The patch e22b886a8a43b147e1994a9f970f678fc0df2033 introduced a bug in the
raid5 subsystem.

The function raid5_quiesce (and resize_stripes) calls 
lock_all_device_hash_locks_irq that disables interrupts and takes a few 
spinlocks, then it calls wait_event_cmd with cmd1 
unlock_all_device_hash_locks_irq(conf) and cmd2 
lock_all_device_hash_locks_irq(conf). cmd1 unlocks the spinlocks and 
enables interrupts, cmd2 disables interrupts and locks the spinlock.

The patch e22b886a8a43b147e1994a9f970f678fc0df2033 adds might_sleep() to a
position where spinlocks are taken, thus it introduces a bug.

This patch removes might_sleep() from wait_event_cmd.

Signed-off-by: Mikulas Patocka <mpato...@redhat.com>

---
 include/linux/wait.h |    1 -
 1 file changed, 1 deletion(-)

Index: linux-2.6/include/linux/wait.h
===================================================================
--- linux-2.6.orig/include/linux/wait.h 2014-12-30 01:19:25.564231262 +0100
+++ linux-2.6/include/linux/wait.h      2015-02-02 15:30:16.766354658 +0100
@@ -363,7 +363,6 @@ do {                                                        
                \
  */
 #define wait_event_cmd(wq, condition, cmd1, cmd2)                      \
 do {                                                                   \
-       might_sleep();                                                  \
        if (condition)                                                  \
                break;                                                  \
        __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
--
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