On Mon, 2 Feb 2015 09:39:02 -0500 (EST) Mikulas Patocka <mpatocka@xxxxxxxxxx>
wrote:
> 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@xxxxxxxxxx>
>
> ---
> 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); \
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
I support this patch.
However in case it doesn't get in, I've queued up a patch to change raid5.c
to use __wait_event_cmd instead...
NeilBrown
Attachment:
pgpPSUlqfa41a.pgp
Description: OpenPGP digital signature
-- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
