From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 080562AF07; Tue, 8 Jul 2025 14:30:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751985020; cv=none; b=uBLuwwuTxh4KcZ7GlTD9Gpn+HYvU/DnGsEAH95/NYMwt8QOuFQpbRJaHpFJE3owLMO+alnPO75PL3lR8k+Rgc2uT8P+WQdvQozYSFSiDjIzU+B+gcT75bFi/s0fpn/JYLNFwmmS2nysrlsJGDjIiBzW9fKjD9ibe4Zdo/woBegk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751985020; c=relaxed/simple; bh=hfmPIOfoH2uX5MA2q6bOJzGVVd9u6N6tqlc0WmZuRQY=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Vc5Kftqdkk8PH3EulhNEdRYi0BCAhWIqZJYhka547xFdNf/veoVWH+mywagmFqi0jUShNQh2Qazvpc2nrMnqkYQjChRl0WZh5E88QCyb0QskiJWiaWvN+AK58Y4A83vgXcPcHkcpDk1ToakMw215S6ZpKlqVa/gijBNR6ALyylM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=n4aM3dRx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="n4aM3dRx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D16B2C4CEED; Tue, 8 Jul 2025 14:30:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751985019; bh=hfmPIOfoH2uX5MA2q6bOJzGVVd9u6N6tqlc0WmZuRQY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=n4aM3dRxK69iFJdv7joPgNvlfgeuNYJNJoKgtkfgmvhrwZ5PaVzbTUKUXfbxg9ctP 7G/J6cfL4jounNhRIWaricFpFRmDKdD7kCGqOH+RsTl0HOAPsf1/UDjsnxL17YJ/// rSQh2+Swd2whDd+cHPjFdrdSGjCglvc9LijEB/mOHLW/X7w1RdKv32ScVEj4cDJThL qPhhuWYWH6nckHuVaJmajpMQM61riTQja266a/Exj97lBb8UNwV+l8IjsLIm1jIaHn V02i2tH47gJCoEnSZRsMgBcE4qo8tvF0GlGHsI/cGHRyNzVO++2AXOoTDDRe490BZO egkoQ3eOyD7dg== Date: Tue, 8 Jul 2025 07:30:17 -0700 From: Jakub Kicinski To: Jiayuan Chen Cc: netdev@vger.kernel.org, mrpre@163.com, syzbot+de6565462ab540f50e47@syzkaller.appspotmail.com, Eric Dumazet , Neal Cardwell , Kuniyuki Iwashima , "David S. Miller" , David Ahern , Paolo Abeni , Simon Horman , David Howells , linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v4] tcp: Correct signedness in skb remaining space calculation Message-ID: <20250708073017.27ab068f@kernel.org> In-Reply-To: <20250707054112.101081-1-jiayuan.chen@linux.dev> References: <20250707054112.101081-1-jiayuan.chen@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 7 Jul 2025 13:41:11 +0800 Jiayuan Chen wrote: > Reported-by: syzbot+de6565462ab540f50e47@syzkaller.appspotmail.com > Fixes: 270a1c3de47e ("tcp: Support MSG_SPLICE_PAGES") > Signed-off-by: Jiayuan Chen > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index 8a3c99246d2e..803a419f4ea0 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -1176,7 +1176,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) > goto do_error; > > while (msg_data_left(msg)) { > - ssize_t copy = 0; > + int copy = 0; nice! FWIW I think we started hitting something like this in prod, not sure what the actual repro is but recently some workloads here moved to 6.9 kernels and I see spikes in warnings in copy from iter that the size is > INT_MAX: WARNING: CPU: 26 PID: 3504902 at include/linux/thread_info.h:249 tcp_sendmsg+0xefd/0x1450 RIP: 0010:tcp_sendmsg (./include/linux/thread_info.h:249 ./include/linux/uio.h:203 ./include/linux/uio.h:221 ./include/net/sock.h:2176 ./include/net/sock.h:2202 net/ipv4/tcp.c:1219 net/ipv4/tcp.c:1355) I'll take this fix via net.