Re: [PATCH] net/af_packet: fix socket close on device stop

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue,  4 Feb 2025 18:45:08 +0200
Tudor Cornea <tudor.cornea@gmail.com> wrote:

> Currently, if we call rte_eth_dev_stop(), the sockets are closed.
> If we attempt to start the port again, socket related operations
> will not work correctly.
> 
> This can be alleviated by closing the socket at the same place in
> which we currently free the memory, in eth_dev_close().
> 
> If an application calls rte_eth_dev_stop() on a port managed
> by the af_packet PMD, the port becomes unusable. This is in contrast
> with ports managed by other drivers (e.g virtio).
> 
> I also managed to reproduce the issue using testpmd.
> 
> sudo ip link add test-veth0 type veth peer name test-veth1
> 
> sudo ip link set test-veth0 up
> sudo ip link set test-veth1 up
> 
> AF_PACKET_ARGS=\
> "blocksz=4096,framesz=2048,framecnt=512,qpairs=1,qdisc_bypass=0"
> 
> sudo ./dpdk-testpmd \
>         -l 0-3 \
>         -m 1024 \
>         --no-huge \
>         --no-shconf \
>         --no-pci \
>         --vdev=net_af_packet0,iface=test-veth0,${AF_PACKET_ARGS} \
>         --vdev=net_af_packet1,iface=test-veth1,${AF_PACKET_ARGS} \
>         -- \
>         -i
> 
> testpmd> start tx_first  
> 
> Forwarding will start, and we will see traffic on the interfaces.
> 
> testpmd> stop
> testpmd> port stop 0  
> Stopping ports...
> Checking link statuses...
> Done
> testpmd> port stop 1  
> Stopping ports...
> Checking link statuses...
> Done
> 
> testpmd> port start 0  
> AFPACKET: eth_dev_macaddr_set(): receive socket not found
> Port 0: CA:65:81:63:81:B2
> Checking link statuses...
> Done
> testpmd> port start 1  
> AFPACKET: eth_dev_macaddr_set(): receive socket not found
> Port 1: CA:12:D0:BE:93:3F
> Checking link statuses...
> Done
> 
> testpmd> start tx_first  
> 
> When we start forwarding again, we can see that there is no traffic
> on the interfaces. This does not happen when testing with other PMD
> drivers (e.g virtio).
> 
> With the patch, the port should re-initialize correctly.
> 
> testpmd> port start 0  
> Port 0: CA:65:81:63:81:B2
> Checking link statuses...
> Done
> 
> Fixes: 364e08f2bbc0 ("af_packet: add PMD for AF_PACKET-based virtual devices")
> 
> Signed-off-by: Tudor Cornea <tudor.cornea@gmail.com>

Makes sense, applied to next-net