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 17:37:28 +0300 [thread overview]
Message-ID: <20210923143728.GD2083@kadam> (raw)
In-Reply-To: <20210923141942.GD2048@kadam>
On Thu, Sep 23, 2021 at 05:19:42PM +0300, Dan Carpenter wrote:
> 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 '!='
I should have checked my output a bit more carefully. I don't want this
one to generate a warning.
> net/mptcp/protocol.c:909 mptcp_frag_can_collapse_to() warn: unsigned subtraction: 'pfrag->size - pfrag->offset' use '!='
Likely "pfrag->offset" can't be larger than "pfrag->size". Smatch has
some code to try track this information but it's not clever enough.
regards,
dan carpenter
next prev parent reply other threads:[~2021-09-23 14:38 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
2021-09-23 14:37 ` Dan Carpenter [this message]
2021-09-23 15:13 ` Paolo Abeni
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