[dpdk-dev] PMD pcap driver: double free or corruption error

[Nicolas Pernas Maradei <nico@emutex.com>]

Hi,

I've been using the PMD pcap driver for a while now. It's very handy for 
testing and running DPDK on systems with no Intel NICs (like my laptop). 
Unfortunately I've found a small issue that's been bothering me a lot. 
It turns out that the PMD pcap driver opens the pcaps/interfaces only at 
init time and close them everytime the port is closed. So if you close 
the port two times in a row you'll get a "double free or corruption" 
error being thrown by libpcap.

You can easily reproduce the error with testpmd doing the following:

sudo  ./x86_64-native-linuxapp-gcc/app/testpmd -c f -n 3 
--vdev=eth_pcap0,rx_pcap=../netronome/client/examples/file.pcap,tx_pcap=out.pcap 
-- --port-topology=chained -i

.....

init (0) eth_pcap0
PMD: Initializing pmd_pcap for eth_pcap0
PMD: Creating pcap-backed ethdev on numa socket 0
EAL: Core 3 is ready (tid=e99fc700)
EAL: Core 2 is ready (tid=ea1fd700)
EAL: Core 1 is ready (tid=ea9fe700)
Interactive-mode selected
Configuring Port 0 (socket 0)
Port 0: 00:00:00:01:02:03
Checking link statuses...
Port 0 Link Up - speed 10000 Mbps - full-duplex
Done
testpmd> port stop all
Stopping ports...
Checking link statuses...
Port 0 Link Down
Done
testpmd> port start all
Port 0: 00:00:00:01:02:03
Checking link statuses...
Port 0 Link Up - speed 10000 Mbps - full-duplex
Done
testpmd> port stop all
Stopping ports...
*** Error in `./x86_64-native-linuxapp-gcc/app/testpmd': double free or 
corruption (!prev): 0x00000000015a9020 ***

I have a fix for it that I'm currently testing and will be submitting 
later on this week. Basically I'm storing the config the driver is 
started with (type of streams and pcap/interface names) and re-opening 
them everytime the user starts the port.

Thanks,
Nico.

-- 
Nicolás Pernas Maradei
Software Engineer
Emutex Ltd.
Callan Centre, National Technology Park, Limerick, Ireland
Phone: +353 (0)61 514496 Ext #872, Mobile: +353 (0)86 7907731
Web: www.emutex.com, Email: nico@emutex.com

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