From: Simon Horman <horms@kernel.org>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: netdev@vger.kernel.org, jhs@mojatatu.com, will@willsroot.io,
stephen@networkplumber.org,
Savino Dicanosa <savy@syst3mfailure.io>
Subject: Re: [Patch v2 net 1/2] netem: Fix skb duplication logic to prevent infinite loops
Date: Tue, 8 Jul 2025 14:18:22 +0100 [thread overview]
Message-ID: <20250708131822.GJ452973@horms.kernel.org> (raw)
In-Reply-To: <20250707195015.823492-2-xiyou.wangcong@gmail.com>
On Mon, Jul 07, 2025 at 12:50:14PM -0700, Cong Wang wrote:
> This patch refines the packet duplication handling in netem_enqueue() to ensure
> that only newly cloned skbs are marked as duplicates. This prevents scenarios
> where nested netem qdiscs with 100% duplication could cause infinite loops of
> skb duplication.
>
> By ensuring the duplicate flag is properly managed, this patch maintains skb
> integrity and avoids excessive packet duplication in complex qdisc setups.
>
> Now we could also get rid of the ugly temporary overwrite of
> q->duplicate.
>
> Fixes: 0afb51e72855 ("[PKT_SCHED]: netem: reinsert for duplication")
> Reported-by: William Liu <will@willsroot.io>
> Reported-by: Savino Dicanosa <savy@syst3mfailure.io>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
next prev parent reply other threads:[~2025-07-08 13:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-07 19:50 [Patch v2 net 0/2] netem: Fix skb duplication logic to prevent infinite loops Cong Wang
2025-07-07 19:50 ` [Patch v2 net 1/2] " Cong Wang
2025-07-08 13:18 ` Simon Horman [this message]
2025-07-08 13:19 ` Jamal Hadi Salim
2025-07-08 19:11 ` Simon Horman
2025-07-08 15:56 ` William Liu
2025-07-08 16:06 ` Jakub Kicinski
2025-07-07 19:50 ` [Patch v2 net 2/2] selftests/tc-testing: Add a nested netem duplicate test Cong Wang
2025-07-08 13:19 ` Simon Horman
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