Re: [dpdk-dev] [dpdk-stable] [PATCH] net/failsafe: fix fd leak

[Stephen Hemminger <stephen@networkplumber.org>]

On Mon, 4 May 2020 18:22:26 +0200
Gaëtan Rivet <grive@u256.net> wrote:

> On 03/05/20 11:33 +0000, Ali Alnubani wrote:
> > Hi,
> >   
> > > -----Original Message-----
> > > From: dev <dev-bounces@dpdk.org> On Behalf Of Ferruh Yigit
> > > Sent: Monday, April 27, 2020 7:56 PM
> > > To: Gaëtan Rivet <grive@u256.net>; wangyunjian
> > > <wangyunjian@huawei.com>
> > > Cc: dev@dpdk.org; jerry.lilijun@huawei.com; xudingke@huawei.com;
> > > stable@dpdk.org
> > > Subject: Re: [dpdk-dev] [dpdk-stable] [PATCH] net/failsafe: fix fd leak
> > > 
> > > On 4/27/2020 12:12 PM, Gaëtan Rivet wrote:  
> > > > On 27/04/20 18:44 +0800, wangyunjian wrote:  
> > > >> From: Yunjian Wang <wangyunjian@huawei.com>
> > > >>
> > > >> Zero is a valid fd. The fd won't be closed thus leading fd leak, when
> > > >> it is zero.
> > > >>
> > > >> Fixes: f234e5bd996d ("net/failsafe: register slaves Rx interrupts")
> > > >> Fixes: 9e0360aebf23 ("net/failsafe: register as Rx interrupt mode")
> > > >> Cc: stable@dpdk.org
> > > >>  
> > > >
> > > > Hello Yunjian,
> > > >
> > > > Nothing prevents a DPDK app from closing 0 and getting it from another
> > > > call, good catch.
> > > >  
> > > >> Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>  
> > > >
> > > > Acked-by: Gaetan Rivet <grive@u256.net>  
> > > 
> > > Applied to dpdk-next-net/master, thanks.  
> > 
> > This patch is causing Testpmd to quit when I issue a "port stop" command. Testpmd log:
> > 
> > """
> > x86_64-native-linuxapp-gcc/build/app/test-pmd/testpmd -n 4 -- -i --forward-mode=mac
> > EAL: Detected 8 lcore(s)
> > EAL: Detected 1 NUMA nodes
> > EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
> > EAL: Selected IOVA mode 'PA'
> > EAL: No available hugepages reported in hugepages-1048576kB
> > EAL: Probing VFIO support...
> > EAL: PCI device 0002:00:02.0 on NUMA socket 0
> > EAL:   probe driver: 15b3:1004 net_mlx4
> > Interactive-mode selected
> > Set mac packet forwarding mode
> > Warning: NUMA should be configured manually by using --port-numa-config and --ring-numa-config parameters along with --numa.
> > testpmd: create a new mbuf pool <mbuf_pool_socket_0>: n=203456, size=2176, socket=0
> > testpmd: preferred mempool ops selected: ring_mp_mc
> > 
> > Warning! port-topology=paired and odd forward ports number, the last port will pair with itself.
> > 
> > Configuring Port 1 (socket 0)
> > Port 1: 00:15:5D:26:2B:00
> > Checking link statuses...
> > Done  
> > testpmd> port stop 1  
> > Stopping ports...
> > Checking link statuses...
> > Done  
> > testpmd>  
> > Stopping port 1...
> > Stopping ports...
> > Done
> > 
> > Shutting down port 1...
> > Closing ports...
> > Done
> > 
> > Bye...
> > """
> > 
> > My terminal gets broken at this point, and I have to reinitialize it with a "reset".

The problem is that you did not blacklist the PCI address of the Mellanox device associated with
your login session (normally this is the PCI device associated with eth0).

By default, DPDK will take over all VF devices it finds as part of the Mellanox device
startup. This means the traffic that was going to the VF associated with eth0 (your ssh)
is now going to DPDK; which is not what you want.

The solution is to either use blacklist (-b option) or whitelist (-w option) to get only
the PCI devices you want to be part of the DPDK.