From aa5cbd103887011b4830355f88fb055f9ad2d556 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 14 Dec 2009 12:49:46 +1100 Subject: md/bitmap: protect against bitmap removal while being updated. A write intent bitmap can be removed from an array while the array is active. When this happens, all IO is suspended and flushed before the bitmap is removed. However it is possible that bitmap_daemon_work is still running to clear old bits from the bitmap. If it is, it can dereference the bitmap after it has been freed. So introduce a new mutex to protect bitmap_daemon_work and get it before destroying a bitmap. This is suitable for any current -stable kernel. Signed-off-by: NeilBrown Cc: stable@kernel.org --- drivers/md/md.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/md/md.c') diff --git a/drivers/md/md.c b/drivers/md/md.c index 5f154ef1e4be..1be7a16a7a53 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -363,6 +363,7 @@ static mddev_t * mddev_find(dev_t unit) mutex_init(&new->open_mutex); mutex_init(&new->reconfig_mutex); + mutex_init(&new->bitmap_mutex); INIT_LIST_HEAD(&new->disks); INIT_LIST_HEAD(&new->all_mddevs); init_timer(&new->safemode_timer); @@ -6625,7 +6626,7 @@ void md_check_recovery(mddev_t *mddev) if (mddev->bitmap) - bitmap_daemon_work(mddev->bitmap); + bitmap_daemon_work(mddev); if (mddev->ro) return; -- cgit v1.2.1