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| author | Miao Xie <miaox@cn.fujitsu.com> | 2014-09-03 21:35:43 +0800 |
|---|---|---|
| committer | Chris Mason <clm@fb.com> | 2014-09-17 13:38:44 -0700 |
| commit | 67a2c45ee7f4f250458279a2e1244679c5d9735c (patch) | |
| tree | 0f1806d2aead6af9629bb701101b75b28863b986 /fs/btrfs/volumes.c | |
| parent | adbbb8631beda8e4e5d2c964b8b47e04cfa0a2ae (diff) | |
| download | blackbird-obmc-linux-67a2c45ee7f4f250458279a2e1244679c5d9735c.tar.gz blackbird-obmc-linux-67a2c45ee7f4f250458279a2e1244679c5d9735c.zip | |
Btrfs: fix use-after-free problem of the device during device replace
The problem is:
Task0(device scan task) Task1(device replace task)
scan_one_device()
mutex_lock(&uuid_mutex)
device = find_device()
mutex_lock(&device_list_mutex)
lock_chunk()
rm_and_free_source_device
unlock_chunk()
mutex_unlock(&device_list_mutex)
check device
Destroying the target device if device replace fails also has the same problem.
We fix this problem by locking uuid_mutex during destroying source device or
target device, just like the device remove operation.
It is a temporary solution, we can fix this problem and make the code more
clear by atomic counter in the future.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs/volumes.c')
| -rw-r--r-- | fs/btrfs/volumes.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index d28e1761fdeb..a15c8ac5d5b3 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -50,7 +50,7 @@ static void __btrfs_reset_dev_stats(struct btrfs_device *dev); static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev); static void btrfs_dev_stat_print_on_load(struct btrfs_device *device); -static DEFINE_MUTEX(uuid_mutex); +DEFINE_MUTEX(uuid_mutex); static LIST_HEAD(fs_uuids); static void lock_chunks(struct btrfs_root *root) @@ -1867,6 +1867,7 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info, { struct btrfs_device *next_device; + mutex_lock(&uuid_mutex); WARN_ON(!tgtdev); mutex_lock(&fs_info->fs_devices->device_list_mutex); if (tgtdev->bdev) { @@ -1886,6 +1887,7 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info, call_rcu(&tgtdev->rcu, free_device); mutex_unlock(&fs_info->fs_devices->device_list_mutex); + mutex_unlock(&uuid_mutex); } static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path, |
