From: NeilBrown Date: Thu, 12 Apr 2012 06:05:06 +0000 (+1000) Subject: md/bitmap: prevent bitmap_daemon_work running while initialising bitmap X-Git-Url: http://git.alex.org.uk md/bitmap: prevent bitmap_daemon_work running while initialising bitmap BugLink: http://bugs.launchpad.net/bugs/987337 commit afbaa90b80b1ec66e5137cc3824746bfdf559b18 upstream. If a bitmap is added while the array is active, it is possible for bitmap_daemon_work to run while the bitmap is being initialised. This is particularly a problem if bitmap_daemon_work sees bitmap->filemap as non-NULL before it has been filled in properly. So hold bitmap_info.mutex while filling in ->filemap to prevent problems. This patch is suitable for any -stable kernel, though it might not apply cleanly before about 3.1. Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman Signed-off-by: Tim Gardner --- diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index 2a8722b..62a8e68 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -1819,7 +1819,9 @@ int bitmap_load(struct mddev *mddev) * re-add of a missing device */ start = mddev->recovery_cp; + mutex_lock(&mddev->bitmap_info.mutex); err = bitmap_init_from_disk(bitmap, start); + mutex_unlock(&mddev->bitmap_info.mutex); if (err) goto out;