From: Simon Horman <horms@kernel.org>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: netdev@vger.kernel.org, jhs@mojatatu.com, jiri@resnulli.us,
mincho@theori.io
Subject: Re: [Patch net 1/2] net_sched: Prevent creation of classes with TC_H_ROOT
Date: Tue, 11 Mar 2025 11:48:35 +0100 [thread overview]
Message-ID: <20250311104835.GJ4159220@kernel.org> (raw)
In-Reply-To: <20250306232355.93864-2-xiyou.wangcong@gmail.com>
On Thu, Mar 06, 2025 at 03:23:54PM -0800, Cong Wang wrote:
> The function qdisc_tree_reduce_backlog() uses TC_H_ROOT as a termination
> condition when traversing up the qdisc tree to update parent backlog
> counters. However, if a class is created with classid TC_H_ROOT, the
> traversal terminates prematurely at this class instead of reaching the
> actual root qdisc, causing parent statistics to be incorrectly maintained.
> In case of DRR, this could lead to a crash as reported by Mingi Cho.
>
> Prevent the creation of any Qdisc class with classid TC_H_ROOT
> (0xFFFFFFFF) across all qdisc types, as suggested by Jamal.
>
> Reported-by: Mingi Cho <mincho@theori.io>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Hi Cong,
This change looks good to me.
But could we get a fixes tag?`
...
next prev parent reply other threads:[~2025-03-11 10:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-06 23:23 [Patch net 0/2] net_sched: Prevent creation of classes with TC_H_ROOT Cong Wang
2025-03-06 23:23 ` [Patch net 1/2] " Cong Wang
2025-03-11 10:48 ` Simon Horman [this message]
2025-03-11 12:47 ` Paolo Abeni
2025-03-11 16:04 ` Simon Horman
2025-03-11 20:07 ` Cong Wang
2025-03-06 23:23 ` [Patch net 2/2] selftests/tc-testing: Add a test case for DRR class " Cong Wang
2025-03-11 16:05 ` Simon Horman
2025-03-12 20:10 ` [Patch net 0/2] net_sched: Prevent creation of classes " patchwork-bot+netdevbpf
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