On Thu, 10 Mar 2022 22:43:47 +0800 Duoming Zhou wrote:

There are race conditions that may lead to null pointer dereferences in
ax25_heartbeat_expiry(), ax25_t1timer_expiry(), ax25_t2timer_expiry(),
ax25_t3timer_expiry() and ax25_idletimer_expiry(), when we use
ax25_kill_by_device() to detach the ax25 device.

None of your last 4 patches applied to our trees.

If you're sending fixes for networking please base them on 
net/master and put [PATCH net] in the subject.