Patch "ovl: fix getcwd() failure after unsuccessful rmdir" has been added to the 4.4-stable tree

Patch "ovl: fix getcwd() failure after unsuccessful rmdir" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ovl: fix getcwd() failure after unsuccessful rmdir

to the 4.4-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:
     ovl-fix-getcwd-failure-after-unsuccessful-rmdir.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From ce9113bbcbf45a57c082d6603b9a9f342be3ef74 Mon Sep 17 00:00:00 2001
From: Rui Wang <rui.y.wang@intel.com>
Date: Fri, 8 Jan 2016 23:09:59 +0800
Subject: ovl: fix getcwd() failure after unsuccessful rmdir

From: Rui Wang <rui.y.wang@intel.com>

commit ce9113bbcbf45a57c082d6603b9a9f342be3ef74 upstream.

ovl_remove_upper() should do d_drop() only after it successfully
removes the dir, otherwise a subsequent getcwd() system call will
fail, breaking userspace programs.

This is to fix: https://bugzilla.kernel.org/show_bug.cgi?id=110491

Signed-off-by: Rui Wang <rui.y.wang@intel.com>
Reviewed-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


---
 fs/overlayfs/dir.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -618,7 +618,8 @@ static int ovl_remove_upper(struct dentr
 	 * sole user of this dentry.  Too tricky...  Just unhash for
 	 * now.
 	 */
-	d_drop(dentry);
+	if (!err)
+		d_drop(dentry);
 	mutex_unlock(&dir->i_mutex);
 
 	return err;


Patches currently in stable-queue which might be from rui.y.wang@intel.com are

queue-4.4/ovl-fix-getcwd-failure-after-unsuccessful-rmdir.patch