From: Igor Putko <igorpetindev@gmail.com>
To: netdev@vger.kernel.org
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, horms@kernel.org,
linux-kernel@vger.kernel.org, Igor Putko <igorpetindev@gmail.com>
Subject: [PATCH] net: core: use WARN_ON_ONCE in datagram iterators
Date: Tue, 14 Jul 2026 11:25:11 +0300 [thread overview]
Message-ID: <20260714082511.2817-1-igorpetindev@gmail.com> (raw)
Datagram fragment iteration helpers check for invalid buffer offsets
using WARN_ON(). In fast-path packet processing routines, a malformed
skb or lower-level driver bug triggering this check can result in
unbounded dmesg logging.
Excessive console logging in data-path contexts introduces severe I/O
latency overhead and risks triggering a DoS or system instability
via log flooding.
Replace WARN_ON() with WARN_ON_ONCE() in __skb_datagram_iter() and
skb_copy_datagram_from_iter(). This ensures anomalous conditions remain
reportable for debugging without spamming the kernel log on repeated
occurrences.
Signed-off-by: Igor Putko <igorpetindev@gmail.com>
---
net/core/datagram.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/core/datagram.c b/net/core/datagram.c
index c285c6465..125b52870 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -416,7 +416,7 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset,
int end;
const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
- WARN_ON(start > offset + len);
+ WARN_ON_ONCE(start > offset + len);
end = start + skb_frag_size(frag);
if ((copy = end - offset) > 0) {
@@ -449,7 +449,7 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset,
skb_walk_frags(skb, frag_iter) {
int end;
- WARN_ON(start > offset + len);
+ WARN_ON_ONCE(start > offset + len);
end = start + frag_iter->len;
if ((copy = end - offset) > 0) {
@@ -570,7 +570,7 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
int end;
const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
- WARN_ON(start > offset + len);
+ WARN_ON_ONCE(start > offset + len);
end = start + skb_frag_size(frag);
if ((copy = end - offset) > 0) {
@@ -594,7 +594,7 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
skb_walk_frags(skb, frag_iter) {
int end;
- WARN_ON(start > offset + len);
+ WARN_ON_ONCE(start > offset + len);
end = start + frag_iter->len;
if ((copy = end - offset) > 0) {
--
2.47.3
reply other threads:[~2026-07-14 8:25 UTC|newest]
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