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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Paolo Abeni <pabeni@redhat.com>
Cc: syzbot <syzbot+263a248eec3e875baa7b@syzkaller.appspotmail.com>,
	davem@davemloft.net, kuba@kernel.org,
	linux-kernel@vger.kernel.org, mathew.j.martineau@linux.intel.com,
	matthieu.baerts@tessares.net, mptcp@lists.linux.dev,
	netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] WARNING in mptcp_sendmsg_frag
Date: Thu, 23 Sep 2021 17:19:42 +0300	[thread overview]
Message-ID: <20210923141942.GD2048@kadam> (raw)
In-Reply-To: <7de92627f85522bf5640defe16eee6c8825f5c55.camel@redhat.com>

On Wed, Sep 22, 2021 at 12:32:56PM +0200, Paolo Abeni wrote:
> 
> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> 
> The debug code helped a bit. It looks like we have singed/unsigned
> comparisons issue

There should be a static checker warning for these.  I have created one
in response to your email.  It turns out there are a couple other
instances of this bug in the same file.

net/mptcp/protocol.c:479 mptcp_subflow_could_cleanup() warn: unsigned subtraction: '(null)' use '!='
net/mptcp/protocol.c:909 mptcp_frag_can_collapse_to() warn: unsigned subtraction: 'pfrag->size - pfrag->offset' use '!='
net/mptcp/protocol.c:1319 mptcp_sendmsg_frag() warn: unsigned subtraction: 'info->size_goal - skb->len' use '!='

regards,
dan carpenter


  parent reply	other threads:[~2021-09-23 14:20 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-15  4:05 [syzbot] WARNING in mptcp_sendmsg_frag syzbot
2021-09-16 14:53 ` Paolo Abeni
2021-09-18 11:50 ` syzbot
2021-09-22 10:32   ` Paolo Abeni
2021-09-22 10:58     ` syzbot
2021-09-23 14:19     ` Dan Carpenter [this message]
2021-09-23 14:37       ` Dan Carpenter
2021-09-23 15:13         ` Paolo Abeni

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