From: Eric Dumazet <edumazet@google.com>
Date: Wed, 8 Jun 2022 16:04:37 +0000 (-0700)
Subject: net: add debug checks in napi_consume_skb and __napi_alloc_skb()
X-Git-Tag: block-6.0-2022-08-12~31^2~386^2~1
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=ee2640df2393141a2975af726802b349d51713be;p=linux-block.git

net: add debug checks in napi_consume_skb and __napi_alloc_skb()

Commit 6454eca81eae ("net: Use lockdep_assert_in_softirq()
in napi_consume_skb()") added a check in napi_consume_skb()
which is a bit weak.

napi_consume_skb() and __napi_alloc_skb() should only
be used from BH context, not from hard irq or nmi context,
otherwise we could have races.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index cf83d9b8f41d..fec75f8bf1f4 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -560,6 +560,7 @@ struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len,
 	struct sk_buff *skb;
 	void *data;
 
+	DEBUG_NET_WARN_ON_ONCE(!in_softirq());
 	len += NET_SKB_PAD + NET_IP_ALIGN;
 
 	/* If requested length is either too small or too big,
@@ -981,7 +982,7 @@ void napi_consume_skb(struct sk_buff *skb, int budget)
 		return;
 	}
 
-	lockdep_assert_in_softirq();
+	DEBUG_NET_WARN_ON_ONCE(!in_softirq());
 
 	if (!skb_unref(skb))
 		return;