Re: [PATCH net-next v2] net: dsa: avoid potential use-after-free error

On Fri, 20 Nov 2020 20:01:49 +0200 Vladimir Oltean wrote:

On Thu, Nov 19, 2020 at 12:09:06PM +0100, Christian Eggers wrote:

quoted

If dsa_switch_ops::port_txtstamp() returns false, clone will be freed
immediately. Shouldn't store a pointer to freed memory.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Fixes: 146d442c2357 ("net: dsa: Keep a pointer to the skb clone for TX timestamping")
---  

IMO this is one of the cases to which the following from
Documentation/process/stable-kernel-rules.rst does not apply:

 - It must fix a real bug that bothers people (not a, "This could be a
   problem..." type thing).

Therefore, specifying "net-next" as the target tree here as opposed to
"net" is the correct choice.

The commit message doesn't really explain what happens after.

Is the dangling pointer ever accessed?