Tcreplay hangs using --netmap and --loop options (ixgbe)

[ds-j-ot]

Description
When I try to replay a file with netmap several times, tcpreplay will always hang on the last loop.
This is what happens:

linux-adm@bnv-Lx-NB:~/pcap$ sudo tcpreplay -i ethtest0 -M 1000 -K --stats 0 -l 10 --netmap smallFlows.pcap Switching network driver for ethtest0 to netmap bypass mode... done! File Cache is enabled Loop 1 of 10... Test start: 2019-06-03 13:46:30.565530 ... Actual: 150000 packets (9600000 bytes) sent in 0.076801 seconds Rated: 124998372.4 Bps, 999.98 Mbps, 1953099.56 pps Loop 2 of 10... Actual: 300000 packets (19200000 bytes) sent in 0.153600 seconds Rated: 125000000.0 Bps, 1000.00 Mbps, 1953125.00 pps Loop 3 of 10... Actual: 450000 packets (28800000 bytes) sent in 0.230401 seconds Rated: 124999457.4 Bps, 999.99 Mbps, 1953116.52 pps Loop 4 of 10... Actual: 600000 packets (38400000 bytes) sent in 0.307200 seconds Rated: 125000000.0 Bps, 1000.00 Mbps, 1953125.00 pps Loop 5 of 10... Actual: 750000 packets (48000000 bytes) sent in 0.384000 seconds Rated: 125000000.0 Bps, 1000.00 Mbps, 1953125.00 pps Loop 6 of 10... Actual: 900000 packets (57600000 bytes) sent in 0.460800 seconds Rated: 125000000.0 Bps, 1000.00 Mbps, 1953125.00 pps Loop 7 of 10... Actual: 1050000 packets (67200000 bytes) sent in 0.537601 seconds Rated: 124999767.4 Bps, 999.99 Mbps, 1953121.36 pps Loop 8 of 10... Actual: 1200000 packets (76800000 bytes) sent in 0.614400 seconds Rated: 125000000.0 Bps, 1000.00 Mbps, 1953125.00 pps Loop 9 of 10...

At that point it stops forever (still using 100% CPU and not being able to abort with CTRL+C).

If I start it with e.g. "-l 5", it hangs on the 4/5 run and so on.

Replaying a single time without "-l" works, aswell as looping forever with "-l 0".

This problem does not occur with another network card (I210) using the igb driver.

System:

• OS: Ubuntu 18.04.2 LTS
• Tcpreplay 4.3.2
• NIC: Intel X550T (ixgbe)

[fklassen]

Looks like a bug. It may be related to the version of netmap you are using. What version are you using?

[ds-j-ot]

I am using the latest master (commit f392508fc896ecac11b4561ac7c9830403c956f7) because on older releases the patched ixgbe driver does not build.

[ds-j-ot]

It seems like nm_tx_pending(ring) always returns true

[fklassen]

Oh, that's bad. Most likely an issue in netmap. I'm quite sure that function was working before.

[fklassen]

@ds-j-ot thanks for looking into this.