From: Sabrina Dubroca <sd@queasysnail.net>
To: Eric Dumazet <edumazet@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Simon Horman <horms@kernel.org>,
Willem de Bruijn <willemb@google.com>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
Michal Kubecek <mkubecek@suse.cz>,
Florian Westphal <fw@strlen.de>
Subject: Re: [PATCH v3 net] udp: do not use skb_release_head_state() before skb_attempt_defer_free()
Date: Wed, 15 Oct 2025 22:04:23 +0200 [thread overview]
Message-ID: <aO_-R4TlViHk_HB7@krikkit> (raw)
In-Reply-To: <20251015052715.4140493-1-edumazet@google.com>
2025-10-15, 05:27:15 +0000, Eric Dumazet wrote:
> Michal reported and bisected an issue after recent adoption
> of skb_attempt_defer_free() in UDP.
>
> The issue here is that skb_release_head_state() is called twice per skb,
> one time from skb_consume_udp(), then a second time from skb_defer_free_flush()
> and napi_consume_skb().
>
> As Sabrina suggested, remove skb_release_head_state() call from
> skb_consume_udp().
>
> Add a DEBUG_NET_WARN_ON_ONCE(skb_nfct(skb)) in skb_attempt_defer_free()
>
> Many thanks to Michal, Sabrina, Paolo and Florian for their help.
>
> Fixes: 6471658dc66c ("udp: use skb_attempt_defer_free()")
> Reported-and-bisected-by: Michal Kubecek <mkubecek@suse.cz>
> Closes: https://lore.kernel.org/netdev/gpjh4lrotyephiqpuldtxxizrsg6job7cvhiqrw72saz2ubs3h@g6fgbvexgl3r/
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Tested-by: Michal Kubecek <mkubecek@suse.cz>
> Cc: Sabrina Dubroca <sd@queasysnail.net>
> Cc: Florian Westphal <fw@strlen.de>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Thanks Eric.
--
Sabrina
next prev parent reply other threads:[~2025-10-15 20:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-15 5:27 [PATCH v3 net] udp: do not use skb_release_head_state() before skb_attempt_defer_free() Eric Dumazet
2025-10-15 20:04 ` Sabrina Dubroca [this message]
2025-10-16 14:10 ` patchwork-bot+netdevbpf
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