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SubjectRe: Patch "ext4: fix memory leak in xattr" has been added to the 3.0-stable tree
On Mon, Oct 14, 2013 at 01:31:23PM -0700, gregkh@linuxfoundation.org wrote:

> If we take the 2nd retry path in ext4_expand_extra_isize_ea, we
> potentionally return from the function without having freed these
> allocations. If we don't do the return, we over-write the previous
> allocation pointers, so we leak either way.
>
> Spotted with Coverity.
>
> [ Fixed by tytso to set is and bs to NULL after freeing these
> pointers, in case in the retry loop we later end up triggering an
> error causing a jump to cleanup, at which point we could have a double
> free bug. -- Ted ]
>
> ---
> fs/ext4/xattr.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> --- a/fs/ext4/xattr.c
> +++ b/fs/ext4/xattr.c
> @@ -1271,6 +1271,8 @@ retry:
> s_min_extra_isize) {
> tried_min_extra_isize++;
> new_extra_isize = s_min_extra_isize;
> + kfree(is); is = NULL;
> + kfree(bs); bs = NULL;
> goto retry;
> }

Because this was different in my local tree I ended up looking it over again
when I rebased. Do we also need the patch below ?

Dave

If we take the retry path here, we end up potentially overwriting bh, leaving
it with an elevated reference count.

Signed-off-by: Dave Jones <davej@fedoraproject.org>

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 03e9beb..1423c48 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1352,6 +1352,7 @@ retry:
new_extra_isize = s_min_extra_isize;
kfree(is); is = NULL;
kfree(bs); bs = NULL;
+ brelse(bh);
goto retry;
}
error = -1;

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