Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
In-Reply-To: <20181011142808.GC32030@nautica>
References: <000000000000fddb150577c15af6@google.com> <20181009020949.GA29622@nautica>
 <CACT4Y+bv5dWx0JwCzTPD3mWJRaMHOtRVcvpV5fdQ5KS7zAF_fA@mail.gmail.com>
 <20181010144059.GA20918@nautica> <CACT4Y+Zx5nDN-H8WfC4WtgK7YeAWZig9WsDr1J4DXZBZb+vgWQ@mail.gmail.com>
 <20181010155814.GC20918@nautica> <CACT4Y+bJvxXeJxbAKCPTm0X608t302Kcq+F7Ccot3_-wx7sdog@mail.gmail.com>
 <20181011131045.GA32030@nautica> <CACT4Y+YvJ-KT4UxtOXpou1xpT3wBASDkt135zr2BwrRi0gv4Tw@mail.gmail.com>
 <CACT4Y+bM4DxysCzhWvhURgBVpnLR4uu+oxhLpdZ3x92cKwtAzA@mail.gmail.com> <20181011142808.GC32030@nautica>
From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Fri, 12 Oct 2018 16:42:01 +0200
Message-ID: <CACT4Y+amrywC10vUSN7DQi0O_cx1Y6WysyktPUNMP_u8RMJoHA@mail.gmail.com>
Subject: Re: 9p/RDMA for syzkaller (Was: BUG: corrupted list in p9_read_work)
To:     Dominique Martinet <asmadeus@codewreck.org>
Cc:     Leon Romanovsky <leon@kernel.org>,
        syzbot <syzbot+2222c34dc40b515f30dc@syzkaller.appspotmail.com>,
        David Miller <davem@davemloft.net>,
        Eric Van Hensbergen <ericvh@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Latchesar Ionkov <lucho@ionkov.net>,
        netdev <netdev@vger.kernel.org>,
        Ron Minnich <rminnich@sandia.gov>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        v9fs-developer@lists.sourceforge.net
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Oct 11, 2018 at 4:28 PM, Dominique Martinet
<asmadeus@codewreck.org> wrote:
> Dmitry Vyukov wrote on Thu, Oct 11, 2018:
>> > Now we are talking!
>> > We generally assume that all modules are simply compiled into kernel.
>> > At least that's we have on syzbot. If somebody can't compile them in,
>> > we can suggest to add modprobe into init.
>> > So this boils down to just writing to /sys/module/rdma_rxe/parameters/add.
>>
>> This fails for me:
>>
>> root@syzkaller:~# echo -n syz1 > /sys/module/rdma_rxe/parameters/add
>> [20992.905406] rdma_rxe: interface syz1 not found
>> bash: echo: write error: Invalid argument
>
> Works here, I just did:
>
> [root@f2 ~]# modprobe rdma_rxe
> [root@f2 ~]# echo -n ens3 > /sys/module/rdma_rxe/parameters/add
>
> dmesg says:
> [   35.595534] rdma_rxe: set rxe0 active
> [   35.595541] rdma_rxe: added rxe0 to ens3
>
>
> Actually for a dummy interface if I try the echo directly the echo
> works, and a verb device is created, and I just confirmed I can use
> it... so not sure why rxe_cfg said EINVAL earlier...
>
> [root@f2 ~]# ip link add dummy0 type dummy
> [root@f2 ~]# ip link set dummy0 up
> [root@f2 ~]# ip addr add 10.1.1.1/24 dev dummy0
> [root@f2 ~]# modprobe rdma_rxe
> [root@f2 ~]# echo -n dummy0 > /sys/module/rdma_rxe/parameters/add
>
>
> (then using my test client:
> [root@f2 src]# ./rcat -s
> INFO:  trans_rdma.c (879), msk_cma_event_handler: CONNECT_REQUEST
> INFO:  trans_rdma.c (862), msk_cma_event_handler: ESTABLISHED
> INFO:  trans_rdma.c (917), msk_cma_event_handler: DISCONNECT EVENT...
>
> [root@f2 src]# ./rcat -c 10.1.1.1
> INFO:  trans_rdma.c (862), msk_cma_event_handler: ESTABLISHED
> ^C
> )
>
>
> I assume your syz1 interface is a tap device as you were saying earlier?
> Got anything in dmesg?

Umm... nope, just a random string.
Don't assume any prior knowledge on my side :)