From 2037a0933bc2894a2f50ae57a1ccf6be192adb76 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Tue, 12 May 2015 19:31:37 -0400 Subject: [PATCH] btrfs: use after free when closing devices __btrfs_close_devices() would call_rcu to free the device, which is racy with list_for_each_entry() accessing the memory to retrieve the next device on the list. Signed-off-by: Sasha Levin Reviewed-by: David Sterba Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 403ed1fdd901..c99f29a52e0b 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -693,13 +693,13 @@ static void free_device(struct rcu_head *head) static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices) { - struct btrfs_device *device; + struct btrfs_device *device, *tmp; if (--fs_devices->opened > 0) return 0; mutex_lock(&fs_devices->device_list_mutex); - list_for_each_entry(device, &fs_devices->devices, dev_list) { + list_for_each_entry_safe(device, tmp, &fs_devices->devices, dev_list) { struct btrfs_device *new_device; struct rcu_string *name; -- 2.20.1