patch "mei: protect mei_cl_mtu from null dereference" added to char-misc-linus

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

mei: protect mei_cl_mtu from null dereference

to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From bcbc0b2e275f0a797de11a10eff495b4571863fc Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <[email protected]>
Date: Thu, 29 Oct 2020 11:54:42 +0200
Subject: mei: protect mei_cl_mtu from null dereference

A receive callback is queued while the client is still connected but can still be called after the client was disconnected. Upon disconnect cl->me_cl is set to NULL, hence we need to check that ME client is not-NULL in mei_cl_mtu to avoid
null dereference.

---
 drivers/misc/mei/client.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 64143d4ec758..9e08a9843bba 100644
@@ -182,11 +182,11 @@ static inline u8 mei_cl_me_id(const struct mei_cl *cl)
  *
  * @cl: host client
  *
- * Return: mtu
+ * Return: mtu or 0 if client is not connected
  */
 static inline size_t mei_cl_mtu(const struct mei_cl *cl)
 {
-	return cl->me_cl->props.max_msg_length;
+	return cl->me_cl ? cl->me_cl->props.max_msg_length : 0;
 }
 
 /**

2.29.2