* [PATCH net-next] net: clear skb->sk in skb_release_head_state()
@ 2025-11-11 15:12 Eric Dumazet
2025-11-12 5:23 ` Aditya Garg
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Eric Dumazet @ 2025-11-11 15:12 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, Kuniyuki Iwashima, Willem de Bruijn, netdev,
eric.dumazet, Eric Dumazet
skb_release_head_state() inlines skb_orphan().
We need to clear skb->sk otherwise we can freeze TCP flows
on a mostly idle host, because skb_fclone_busy() would
return true as long as the packet is not yet processed by
skb_defer_free_flush().
Fixes: 1fcf572211da ("net: allow skb_release_head_state() to be called multiple times")
Fixes: e20dfbad8aab ("net: fix napi_consume_skb() with alien skbs")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/core/skbuff.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 4f4d7ab7057f16bcf88f29827a45a9f4a8f43d5c..f34372666e67cee5329d3ba1d3c86f8622facac3 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1152,6 +1152,7 @@ void skb_release_head_state(struct sk_buff *skb)
#endif
skb->destructor = NULL;
+ skb->sk = NULL;
}
nf_reset_ct(skb);
skb_ext_reset(skb);
--
2.52.0.rc1.455.g30608eb744-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH net-next] net: clear skb->sk in skb_release_head_state()
2025-11-11 15:12 [PATCH net-next] net: clear skb->sk in skb_release_head_state() Eric Dumazet
@ 2025-11-12 5:23 ` Aditya Garg
2025-11-12 5:54 ` Kuniyuki Iwashima
2025-11-12 15:00 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Aditya Garg @ 2025-11-12 5:23 UTC (permalink / raw)
To: Eric Dumazet
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Simon Horman,
Kuniyuki Iwashima, Willem de Bruijn, netdev, eric.dumazet,
ssengar, gargaditya
On Tue, Nov 11, 2025 at 03:12:35PM +0000, Eric Dumazet wrote:
> skb_release_head_state() inlines skb_orphan().
>
> We need to clear skb->sk otherwise we can freeze TCP flows
> on a mostly idle host, because skb_fclone_busy() would
> return true as long as the packet is not yet processed by
> skb_defer_free_flush().
>
> Fixes: 1fcf572211da ("net: allow skb_release_head_state() to be called multiple times")
> Fixes: e20dfbad8aab ("net: fix napi_consume_skb() with alien skbs")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
> net/core/skbuff.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 4f4d7ab7057f16bcf88f29827a45a9f4a8f43d5c..f34372666e67cee5329d3ba1d3c86f8622facac3 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -1152,6 +1152,7 @@ void skb_release_head_state(struct sk_buff *skb)
>
> #endif
> skb->destructor = NULL;
> + skb->sk = NULL;
> }
> nf_reset_ct(skb);
> skb_ext_reset(skb);
> --
> 2.52.0.rc1.455.g30608eb744-goog
>
Tested-by: Aditya Garg <gargaditya@linux.microsoft.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net-next] net: clear skb->sk in skb_release_head_state()
2025-11-11 15:12 [PATCH net-next] net: clear skb->sk in skb_release_head_state() Eric Dumazet
2025-11-12 5:23 ` Aditya Garg
@ 2025-11-12 5:54 ` Kuniyuki Iwashima
2025-11-12 15:00 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Kuniyuki Iwashima @ 2025-11-12 5:54 UTC (permalink / raw)
To: Eric Dumazet
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Simon Horman,
Willem de Bruijn, netdev, eric.dumazet
On Tue, Nov 11, 2025 at 7:12 AM Eric Dumazet <edumazet@google.com> wrote:
>
> skb_release_head_state() inlines skb_orphan().
>
> We need to clear skb->sk otherwise we can freeze TCP flows
> on a mostly idle host, because skb_fclone_busy() would
> return true as long as the packet is not yet processed by
> skb_defer_free_flush().
>
> Fixes: 1fcf572211da ("net: allow skb_release_head_state() to be called multiple times")
> Fixes: e20dfbad8aab ("net: fix napi_consume_skb() with alien skbs")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net-next] net: clear skb->sk in skb_release_head_state()
2025-11-11 15:12 [PATCH net-next] net: clear skb->sk in skb_release_head_state() Eric Dumazet
2025-11-12 5:23 ` Aditya Garg
2025-11-12 5:54 ` Kuniyuki Iwashima
@ 2025-11-12 15:00 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2025-11-12 15:00 UTC (permalink / raw)
To: Eric Dumazet
Cc: davem, kuba, pabeni, horms, kuniyu, willemb, netdev, eric.dumazet
Hello:
This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Tue, 11 Nov 2025 15:12:35 +0000 you wrote:
> skb_release_head_state() inlines skb_orphan().
>
> We need to clear skb->sk otherwise we can freeze TCP flows
> on a mostly idle host, because skb_fclone_busy() would
> return true as long as the packet is not yet processed by
> skb_defer_free_flush().
>
> [...]
Here is the summary with links:
- [net-next] net: clear skb->sk in skb_release_head_state()
https://git.kernel.org/netdev/net-next/c/26b8986a18c1
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-11-11 15:12 [PATCH net-next] net: clear skb->sk in skb_release_head_state() Eric Dumazet
2025-11-12 5:23 ` Aditya Garg
2025-11-12 5:54 ` Kuniyuki Iwashima
2025-11-12 15:00 ` patchwork-bot+netdevbpf
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