Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski [off-list ref]:

On Wed, 17 Jun 2026 02:05:18 +0000 you wrote:

Each PPP control protocol (LCP/IPCP/IPV6CP) embedded in struct ppp
registers a timer via timer_setup(). That struct ppp is the
hdlc->state allocation, which detach_hdlc_protocol() frees with kfree()
in both teardown paths: unregister_hdlc_device() and the re-attach inside
attach_hdlc_protocol().

The ppp proto never registered a .detach callback, so
detach_hdlc_protocol() performs no timer synchronization before the
kfree(). The only cancel, timer_delete(&proto->timer) in ppp_cp_event(),
is partial (it does not wait for a running callback) and only runs on the
->CLOSED transition; ppp_stop()/ppp_close() do not sync either. A
ppp_timer callback already executing (blocked on ppp->lock) survives the
kfree and then dereferences proto->state / ppp->lock in freed memory,
leading to a use-after-free.

[...]

Here is the summary with links:
  - [net] net/wan/hdlc_ppp: sync per-proto timers before freeing hdlc state
    https://git.kernel.org/netdev/net/c/c78a4e41ab5e

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html