From: Jakub Kicinski <kuba@kernel.org>
To: Xiang Mei <xmei5@asu.edu>
Cc: security@kernel.org, netdev@vger.kernel.org, toke@toke.dk,
xiyou.wangcong@gmail.com, cake@lists.bufferbloat.net,
bestswngs@gmail.com
Subject: Re: [PATCH net v7 1/2] net/sched: sch_cake: Fix incorrect qlen reduction in cake_drop
Date: Thu, 27 Nov 2025 15:36:44 -0800 [thread overview]
Message-ID: <20251127153644.55ef4796@kernel.org> (raw)
In-Reply-To: <20251126194513.3984722-1-xmei5@asu.edu>
On Wed, 26 Nov 2025 12:45:12 -0700 Xiang Mei wrote:
> In cake_drop(), qdisc_tree_reduce_backlog() is used to update the qlen
> and backlog of the qdisc hierarchy. Its caller, cake_enqueue(), assumes
> that the parent qdisc will enqueue the current packet. However, this
> assumption breaks when cake_enqueue() returns NET_XMIT_CN: the parent
> qdisc stops enqueuing current packet, leaving the tree qlen/backlog
> accounting inconsistent. This mismatch can lead to a NULL dereference
> (e.g., when the parent Qdisc is qfq_qdisc).
This series does not apply, please rebase on netdev/net/main.
--
pw-bot: cr
next prev parent reply other threads:[~2025-11-27 23:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-26 19:45 [PATCH net v7 1/2] net/sched: sch_cake: Fix incorrect qlen reduction in cake_drop Xiang Mei
2025-11-26 19:45 ` [PATCH net v7 2/2] selftests/tc-testing: Test CAKE scheduler when enqueue drops packets Xiang Mei
2025-11-27 9:14 ` Toke Høiland-Jørgensen
2025-11-27 18:22 ` Cong Wang
2025-11-27 9:14 ` [PATCH net v7 1/2] net/sched: sch_cake: Fix incorrect qlen reduction in cake_drop Toke Høiland-Jørgensen
2025-11-27 18:21 ` Cong Wang
2025-11-27 23:36 ` Jakub Kicinski [this message]
2025-11-28 0:16 ` Xiang Mei
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