From: Jakub Kicinski <kuba@kernel.org>
To: Jiakai Xu <xujiakai24@mails.ucas.ac.cn>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
"David S . Miller" <davem@davemloft.net>,
Breno Leitao <leitao@debian.org>,
Eric Dumazet <edumazet@google.com>,
Ernestas Kulik <ernestas.k@iconn-networks.com>,
Kees Cook <kees@kernel.org>,
Kuniyuki Iwashima <kuniyu@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>
Subject: Re: [PATCH v2] llc: Fix race between sock_orphan() and timer callback in llc_sk_free()
Date: Tue, 2 Jun 2026 13:30:02 -0700 [thread overview]
Message-ID: <20260602133002.3ed70fc3@kernel.org> (raw)
In-Reply-To: <20260529020059.3024038-1-xujiakai24@mails.ucas.ac.cn>
On Fri, 29 May 2026 02:00:59 +0000 Jiakai Xu wrote:
> In llc_ui_release(), sock_orphan() was called before llc_sk_free()
> stopped all LLC timers. A pending timer callback
> (llc_conn_ack_tmr_cb()->llc_process_tmr_ev()->llc_conn_state_process())
> could fire between these two operations and dereference the
> NULL sk->sk_socket that sock_orphan() sets, causing a kernel
> page fault.
>
> Fix the race by moving sock_orphan() into llc_sk_free(), after
> llc_sk_stop_all_timers() has completed. This guarantees that
> all timers are stopped before the socket is orphaned, eliminating
> the window for the race.
Sashiko points out that there's more issues if the timer runs after
llc_ui_release(). Can you reliably reproduce this? Have you checked
that this change is sufficient? Sashiko says that llc->dev may
disappear even tho we don't clear that pointer in _release().
--
pw-bot: cr
next prev parent reply other threads:[~2026-06-02 20:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-29 2:00 [PATCH v2] llc: Fix race between sock_orphan() and timer callback in llc_sk_free() Jiakai Xu
2026-06-02 20:30 ` Jakub Kicinski [this message]
2026-06-03 1:30 ` Jiakai Xu
2026-06-03 2:11 ` Jakub Kicinski
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