From 2a2275d630b982e5f90206f9bc497f6695a3ec5d Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 26 Jan 2007 00:57:11 -0800 Subject: [PATCH] md: fix potential memalloc deadlock in md If a GFP_KERNEL allocation is attempted in md while the mddev_lock is held, it is possible for a deadlock to eventuate. This happens if the array was marked 'clean', and the memalloc triggers a write-out to the md device. For the writeout to succeed, the array must be marked 'dirty', and that requires getting the mddev_lock. So, before attempting a GFP_KERNEL allocation while holding the lock, make sure the array is marked 'dirty' (unless it is currently read-only). Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/raid1.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/md/raid1.c') diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index ab74d40cac98..97ee870b265d 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -2104,6 +2104,8 @@ static int raid1_reshape(mddev_t *mddev) return -EINVAL; } + md_allow_write(mddev); + raid_disks = mddev->raid_disks + mddev->delta_disks; if (raid_disks < conf->raid_disks) { -- cgit