From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120419210819.541656558@linuxfoundation.org> Date: Thu, 19 Apr 2012 14:08:28 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, NeilBrown Subject: [ 10/68] md/bitmap: prevent bitmap_daemon_work running while initialising bitmap In-Reply-To: <20120419210923.GA18589@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown 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 --- drivers/md/bitmap.c | 2 ++ 1 file changed, 2 insertions(+) --- 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;