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 09:32:50 +0900 |
| commit | 0e73b1f4f61142e32ec5acbda8e50bfc79dbec87 (patch) | |
| tree | 92206b3778b5932cbafb6b6eff96a13a24386a0d /fs | |
| parent | 9a18274e9444e3581a6ba7479ddad080d1be63c0 (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 8553dfb310af..5860ca232c71 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2730,14 +2730,16 @@ 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; |