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[95.25.161.220]) by smtp.gmail.com with ESMTPSA id 38308e7fff4ca-39c84b9382esm30676591fa.29.2026.07.14.01.25.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jul 2026 01:25:15 -0700 (PDT) From: Igor Putko 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 Subject: [PATCH] net: core: use WARN_ON_ONCE in datagram iterators Date: Tue, 14 Jul 2026 11:25:11 +0300 Message-ID: <20260714082511.2817-1-igorpetindev@gmail.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 --- 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 *sk= b, int offset, int end; const skb_frag_t *frag =3D &skb_shinfo(skb)->frags[i]; =20 - WARN_ON(start > offset + len); + WARN_ON_ONCE(start > offset + len); =20 end =3D start + skb_frag_size(frag); if ((copy =3D end - offset) > 0) { @@ -449,7 +449,7 @@ static int __skb_datagram_iter(const struct sk_buff *sk= b, int offset, skb_walk_frags(skb, frag_iter) { int end; =20 - WARN_ON(start > offset + len); + WARN_ON_ONCE(start > offset + len); =20 end =3D start + frag_iter->len; if ((copy =3D end - offset) > 0) { @@ -570,7 +570,7 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, in= t offset, int end; const skb_frag_t *frag =3D &skb_shinfo(skb)->frags[i]; =20 - WARN_ON(start > offset + len); + WARN_ON_ONCE(start > offset + len); =20 end =3D start + skb_frag_size(frag); if ((copy =3D end - offset) > 0) { @@ -594,7 +594,7 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, in= t offset, skb_walk_frags(skb, frag_iter) { int end; =20 - WARN_ON(start > offset + len); + WARN_ON_ONCE(start > offset + len); =20 end =3D start + frag_iter->len; if ((copy =3D end - offset) > 0) { --=20 2.47.3