Messages in this thread Patch in this message | | | Date | Mon, 2 Feb 2015 09:39:02 -0500 (EST) | From | Mikulas Patocka <> | Subject | [PATCH] Remove might_sleep from wait_event_cmd |
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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 <mpatocka@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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