From: Eric Dumazet <edumazet@google.com>
Date: Mon, 16 Feb 2026 19:36:53 +0000 (+0000)
Subject: net: do not delay zero-copy skbs in skb_attempt_defer_free()
X-Git-Tag: v7.0-rc1~44^2~22
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0943404b1f3b178e1e54386dadcbf4f2729c7762;p=thirdparty%2Fkernel%2Flinux.git

net: do not delay zero-copy skbs in skb_attempt_defer_free()

After the blamed commit, TCP tx zero copy notifications could be
arbitrarily delayed and cause regressions in applications waiting
for them.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: e20dfbad8aab ("net: fix napi_consume_skb() with alien skbs")
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260216193653.627617-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 699c401a5eae..dc47d3efc72e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -7266,10 +7266,15 @@ void skb_attempt_defer_free(struct sk_buff *skb)
 {
 	struct skb_defer_node *sdn;
 	unsigned long defer_count;
-	int cpu = skb->alloc_cpu;
 	unsigned int defer_max;
 	bool kick;
+	int cpu;
 
+	/* zero copy notifications should not be delayed. */
+	if (skb_zcopy(skb))
+		goto nodefer;
+
+	cpu = skb->alloc_cpu;
 	if (cpu == raw_smp_processor_id() ||
 	    WARN_ON_ONCE(cpu >= nr_cpu_ids) ||
 	    !cpu_online(cpu)) {