From 55793c0d0381176e727389325d9a47f7f0b5387f Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 26 Apr 2013 15:20:23 +0000 Subject: [PATCH] btrfs: read entire device info under lock There's a theoretical possibility of reading stale (or even more theoretically, freed) data from DEV_INFO ioctl when the device would disappear between an early mutex unlock and data being copied from the device structure. Signed-off-by: David Sterba Signed-off-by: Josef Bacik --- fs/btrfs/ioctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 3aa3750..0de4a2f 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2432,7 +2432,6 @@ static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg) mutex_lock(&fs_devices->device_list_mutex); dev = btrfs_find_device(root->fs_info, di_args->devid, s_uuid, NULL); - mutex_unlock(&fs_devices->device_list_mutex); if (!dev) { ret = -ENODEV; @@ -2456,6 +2455,7 @@ static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg) } out: + mutex_unlock(&fs_devices->device_list_mutex); if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args))) ret = -EFAULT; -- 2.7.4