diff options
| author | Lukas Czerner <lczerner@redhat.com> | 2011-05-20 13:55:29 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-06-03 10:33:48 +0900 |
| commit | 1db58ae0a6e032378326412bd446ea23591ff50c (patch) | |
| tree | 192eff2166620883814ebfa182e2b5f56d22b746 /fs | |
| parent | aa0ff541cfa5935a5d52f3807c8a4993c46a2799 (diff) | |
ext4: fix possible use-after-free in ext4_remove_li_request()
commit 1bb933fb1fa8e4cb337a0d5dfd2ff4c0dc2073e8 upstream.
We need to take reference to the s_li_request after we take a mutex,
because it might be freed since then, hence result in accessing old
already freed memory. Also we should protect the whole
ext4_remove_li_request() because ext4_li_info might be in the process of
being freed in ext4_lazyinit_thread().
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/super.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 243deb021e7b..f3e1b1886777 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2716,14 +2716,16 @@ static void ext4_remove_li_request(struct ext4_li_request *elr) static void ext4_unregister_li_request(struct super_block *sb) { - struct ext4_li_request *elr = EXT4_SB(sb)->s_li_request; - - if (!ext4_li_info) + mutex_lock(&ext4_li_mtx); + if (!ext4_li_info) { + mutex_unlock(&ext4_li_mtx); return; + } mutex_lock(&ext4_li_info->li_list_mtx); - ext4_remove_li_request(elr); + ext4_remove_li_request(EXT4_SB(sb)->s_li_request); mutex_unlock(&ext4_li_info->li_list_mtx); + mutex_unlock(&ext4_li_mtx); } static struct task_struct *ext4_lazyinit_task; |