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Date:   Fri, 1 Nov 2019 14:48:17 -0400
From:   Sasha Levin <sashal@kernel.org>
To:     Xin Long <lucien.xin@gmail.com>
Cc:     "Rantala, Tommi T. (Nokia - FI/Espoo)" <tommi.t.rantala@nokia.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "syzbot+d44f7bbebdea49dbc84a@syzkaller.appspotmail.com" 
        <syzbot+d44f7bbebdea49dbc84a@syzkaller.appspotmail.com>,
        "marcelo.leitner@gmail.com" <marcelo.leitner@gmail.com>
Subject: Re: [PATCH 4.14 024/119] sctp: change sctp_prot .no_autobind with
 true
Message-ID: <20191101184817.GU1554@sasha-vm>
References: <20191027203259.948006506@linuxfoundation.org>
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On Sat, Nov 02, 2019 at 01:58:33AM +0800, Xin Long wrote:
>On Thu, Oct 31, 2019 at 8:10 PM Sasha Levin <sashal@kernel.org> wrote:
>>
>> On Thu, Oct 31, 2019 at 05:14:15PM +0800, Xin Long wrote:
>> >On Thu, Oct 31, 2019 at 3:54 PM Rantala, Tommi T. (Nokia - FI/Espoo)
>> ><tommi.t.rantala@nokia.com> wrote:
>> >>
>> >> On Sun, 2019-10-27 at 22:00 +0100, Greg Kroah-Hartman wrote:
>> >> > From: Xin Long <lucien.xin@gmail.com>
>> >> >
>> >> > [ Upstream commit 63dfb7938b13fa2c2fbcb45f34d065769eb09414 ]
>> >> >
>> >> > syzbot reported a memory leak:
>> >> >
>> >> >   BUG: memory leak, unreferenced object 0xffff888120b3d380 (size 64):
>> >> >   backtrace:
>> >> >
>> >> >     [...] slab_alloc mm/slab.c:3319 [inline]
>> >> >     [...] kmem_cache_alloc+0x13f/0x2c0 mm/slab.c:3483
>> >> >     [...] sctp_bucket_create net/sctp/socket.c:8523 [inline]
>> >> >     [...] sctp_get_port_local+0x189/0x5a0 net/sctp/socket.c:8270
>> >> >     [...] sctp_do_bind+0xcc/0x200 net/sctp/socket.c:402
>> >> >     [...] sctp_bindx_add+0x4b/0xd0 net/sctp/socket.c:497
>> >> >     [...] sctp_setsockopt_bindx+0x156/0x1b0 net/sctp/socket.c:1022
>> >> >     [...] sctp_setsockopt net/sctp/socket.c:4641 [inline]
>> >> >     [...] sctp_setsockopt+0xaea/0x2dc0 net/sctp/socket.c:4611
>> >> >     [...] sock_common_setsockopt+0x38/0x50 net/core/sock.c:3147
>> >> >     [...] __sys_setsockopt+0x10f/0x220 net/socket.c:2084
>> >> >     [...] __do_sys_setsockopt net/socket.c:2100 [inline]
>> >> >
>> >> > It was caused by when sending msgs without binding a port, in the path:
>> >> > inet_sendmsg() -> inet_send_prepare() -> inet_autobind() ->
>> >> > .get_port/sctp_get_port(), sp->bind_hash will be set while bp->port is
>> >> > not. Later when binding another port by sctp_setsockopt_bindx(), a new
>> >> > bucket will be created as bp->port is not set.
>> >> >
>> >> > sctp's autobind is supposed to call sctp_autobind() where it does all
>> >> > things including setting bp->port. Since sctp_autobind() is called in
>> >> > sctp_sendmsg() if the sk is not yet bound, it should have skipped the
>> >> > auto bind.
>> >> >
>> >> > THis patch is to avoid calling inet_autobind() in inet_send_prepare()
>> >> > by changing sctp_prot .no_autobind with true, also remove the unused
>> >> > .get_port.
>> >>
>> >> Hi,
>> >>
>> >> I'm seeing SCTP oops in 4.14.151, reproducible easily with iperf:
>> >>
>> >> # iperf3 -s -1 &
>> >> # iperf3 -c localhost --sctp
>> >>
>> >> This patch was also included in 4.19.81, but there it seems to be working
>> >> fine.
>> >>
>> >> Any ideas if this patch is valid for 4.14, or what's missing in 4.14 to
>> >> make this work?
>> >pls get this commit into 4.14, which has been in 4.19:
>> >
>> >commit 644fbdeacf1d3edd366e44b8ba214de9d1dd66a9
>> >Author: Xin Long <lucien.xin@gmail.com>
>> >Date:   Sun May 20 16:39:10 2018 +0800
>> >
>> >    sctp: fix the issue that flags are ignored when using kernel_connect
>>
>> Care to send a backport?
>Sure, I haven't yet sent a backport for 4.14.y
>After I do the cherry-pick, what's the next step? Post it upstream
>with CCing someone ?

Just make sure stable@vger.kernel.org is Cc'ed.

-- 
Thanks,
Sasha