This is a note to let you know that I've just added the patch titled
ext4: fix possible use-after-free in
to the 2.6.38-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-fix-possible-use-after-free-in.patch
and it can be found in the queue-2.6.38 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 1bb933fb1fa8e4cb337a0d5dfd2ff4c0dc2073e8 Mon Sep 17 00:00:00 2001
From: Lukas Czerner <[email protected]>
Date: Fri, 20 May 2011 13:55:29 -0400
Subject: ext4: fix possible use-after-free in
ext4_remove_li_request()
From: Lukas Czerner <[email protected]>
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 <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>
Reviewed-by: Eric Sandeen <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/ext4/super.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2716,14 +2716,16 @@ static void ext4_remove_li_request(struc
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;
Patches currently in stable-queue which might be from [email protected] are
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