[PATCH] md: fix oops in error-handling

During early MD setup (superblock reading), we don't have a personality yet.
But the error-handling code tries to dereference mddev->pers.  Fix.

Acked-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index a5286beddcf..b6d16022a53 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4592,6 +4592,8 @@ void md_error(mddev_t *mddev, mdk_rdev_t *rdev)
                 __builtin_return_address(0),__builtin_return_address(1),
                 __builtin_return_address(2),__builtin_return_address(3));
 */
+        if (!mddev->pers)
+                return;
         if (!mddev->pers->error_handler)
                 return;
         mddev->pers->error_handler(mddev,rdev);