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-Tag: v3.0.29~8 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=a10d1f32dbf1b9f74b6b6ba1571ee3f7a1bd3883;p=karo-tx-linux.git md/bitmap: prevent bitmap_daemon_work running while initialising bitmap 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 --- diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index 703a3fa831bc..2eba9a12a6ab 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -1897,7 +1897,9 @@ int bitmap_load(mddev_t *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;