Re: [dpdk-dev] [PATCH 1/2] net/mlx5: fix return value of start operation

[Olivier Matz <olivier.matz@6wind.com>]

On Thu, Jan 18, 2018 at 02:00:42PM +0100, Olivier Matz wrote:
> On error, mlx5_dev_start() does not return a negative value
> as it is supposed to do. The consequence is that the application
> (ex: testpmd) does not notice that the port is not started
> and begins the rxtx on an uninitialized port, which crashes.
> 
> Fixes: e1016cb73383 ("net/mlx5: fix Rx interrupts management")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>

For reference, here is how to reproduce the problem.


The topology of the target:

   socket 0                 socket 1
  +---------------------+  +---------------------+
  |        c0        c1 |  |        c0        c1 |
  | +-------+ +-------+ |  | +-------+ +-------+ |
  | |  0| 16| |  1| 17| |  | |  8| 24| |  9| 25| |
  | +-------+ +-------+ |  | +-------+ +-------+ |
  |        c2        c3 |  |        c2        c3 |
  | +-------+ +-------+ |  | +-------+ +-------+ |
  | |  2| 18| |  3| 19| |  | | 10| 26| | 11| 27| |
  | +-------+ +-------+ |  | +-------+ +-------+ |
  |        c4        c5 |  |        c4        c5 |
  | +-------+ +-------+ |  | +-------+ +-------+ |
  | |  4| 20| |  5| 21| |  | | 12| 28| | 13| 29| |
  | +-------+ +-------+ |  | +-------+ +-------+ |
  |        c6        c7 |  |        c6        c7 |
  | +-------+ +-------+ |  | +-------+ +-------+ |
  | |  6| 22| |  7| 23| |  | | 14| 30| | 15| 31| |
  | +-------+ +-------+ |  | +-------+ +-------+ |
  +---------------------+  +---------------------+

The cx4 devices are on socket 1, but I use cores and memory from
socket 0. I know it is not optimal, but it should work.



root@dut-cx4:~# cd dpdk.org
root@dut-cx4:~/dpdk.org# make config T=x86_64-native-linuxapp-gcc
root@dut-cx4:~/dpdk.org# make -j32
root@dut-cx4:~/dpdk.org# mkdir -p /mnt/huge
root@dut-cx4:~/dpdk.org# mount -t hugetlbfs nodev /mnt/huge
root@dut-cx4:~/dpdk.org# echo 256 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
root@dut-cx4:~/dpdk.org# testpmd -l 0,2 -- --total-num-mbufs=16384 -i --port-topology=chained --no-numa
EAL: Detected 32 lcore(s)
EAL: No free hugepages reported in hugepages-1048576kB
EAL: Probing VFIO support...
EAL: PCI device 0000:02:00.0 on NUMA socket 0
EAL:   probe driver: 8086:1572 net_i40e
EAL: PCI device 0000:02:00.1 on NUMA socket 0
EAL:   probe driver: 8086:1572 net_i40e
EAL: PCI device 0000:02:00.2 on NUMA socket 0
EAL:   probe driver: 8086:1572 net_i40e
EAL: PCI device 0000:02:00.3 on NUMA socket 0
EAL:   probe driver: 8086:1572 net_i40e
EAL: PCI device 0000:04:00.0 on NUMA socket 0
EAL:   probe driver: 14e4:16d7 net_bnxt
EAL: PCI device 0000:04:00.1 on NUMA socket 0
EAL:   probe driver: 14e4:16d7 net_bnxt
EAL: PCI device 0000:06:00.0 on NUMA socket 0
EAL:   probe driver: 8086:1521 net_e1000_igb
EAL: PCI device 0000:83:00.0 on NUMA socket 1
EAL:   probe driver: 8086:10fb net_ixgbe
EAL: PCI device 0000:83:00.1 on NUMA socket 1
EAL:   probe driver: 8086:10fb net_ixgbe
EAL: PCI device 0000:86:00.0 on NUMA socket 1
EAL:   probe driver: 15b3:1013 net_mlx5
PMD: net_mlx5: PCI information matches, using device "mlx5_0" (SR-IOV: false)
PMD: net_mlx5: 1 port(s) detected
PMD: net_mlx5: MPS is disabled
PMD: net_mlx5: port 1 MAC address is e4:1d:2d:e7:0d:06
EAL: PCI device 0000:86:00.1 on NUMA socket 1
EAL:   probe driver: 15b3:1013 net_mlx5
PMD: net_mlx5: PCI information matches, using device "mlx5_1" (SR-IOV: false)
PMD: net_mlx5: 1 port(s) detected
PMD: net_mlx5: MPS is disabled
PMD: net_mlx5: port 1 MAC address is e4:1d:2d:e7:0d:07
Interactive-mode selected
USER1: create a new mbuf pool <mbuf_pool_socket_0>: n=16384, size=2176, socket=0
Configuring Port 0 (socket 0)
PMD: net_mlx5: 0x1459e40: TX queues number update: 0 -> 1
PMD: net_mlx5: 0x1459e40: RX queues number update: 0 -> 1
PMD: net_mlx5: cannot allocate CQ for drop queue
PMD: net_mlx5: 0x1459e40: Drop queue allocation failed: Unknown error -1
Port 0: E4:1D:2D:E7:0D:06
Configuring Port 1 (socket 0)
PMD: net_mlx5: 0x145dec0: TX queues number update: 0 -> 1
PMD: net_mlx5: 0x145dec0: RX queues number update: 0 -> 1
PMD: net_mlx5: cannot allocate CQ for drop queue
PMD: net_mlx5: 0x145dec0: Drop queue allocation failed: Unknown error -1
Port 1: E4:1D:2D:E7:0D:07
Checking link statuses...
Done
testpmd> start
Segmentation fault (core dumped)