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([2405:201:682f:389d:9cfe:b2cf:9d3f:f1f1]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7d15fcfd0cfsm6413100b3a.65.2025.11.28.19.42.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Nov 2025 19:42:40 -0800 (PST) From: Deepanshu Kartikey To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org Cc: linux-hams@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Deepanshu Kartikey , syzbot+d7abc36bbbb6d7d40b58@syzkaller.appspotmail.com Subject: [PATCH] net: netrom: fix memory leak in nr_output() Date: Sat, 29 Nov 2025 09:12:32 +0530 Message-ID: <20251129034232.405203-1-kartikey406@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-hams@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When nr_output() fragments a large packet, it calls sock_alloc_send_skb() in a loop to allocate skbs for each fragment. If this allocation fails, the function returns without freeing the original skb that was passed in, causing a memory leak. Add the missing kfree_skb() call before returning on allocation failure. Reported-by: syzbot+d7abc36bbbb6d7d40b58@syzkaller.appspotmail.com Tested-by: syzbot+d7abc36bbbb6d7d40b58@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d7abc36bbbb6d7d40b58 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Deepanshu Kartikey --- net/netrom/nr_out.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/netrom/nr_out.c b/net/netrom/nr_out.c index 5e531394a724..2b3cbceb0b52 100644 --- a/net/netrom/nr_out.c +++ b/net/netrom/nr_out.c @@ -43,8 +42,11 @@ void nr_output(struct sock *sk, struct sk_buff *skb) frontlen = skb_headroom(skb); while (skb->len > 0) { - if ((skbn = sock_alloc_send_skb(sk, frontlen + NR_MAX_PACKET_SIZE, 0, &err)) == NULL) skbn = sock_alloc_send_skb(sk, frontlen + NR_MAX_PACKET_SIZE, 0, &err); if (skbn == NULL) { + kfree_skb(skb); return; + } skb_reserve(skbn, frontlen); -- 2.43.0