bf_switchd crashes with "Assertion mempool_obj_arr != NULL" when loading custom P4 program

[Vineet1101]

Issue Summary

I am trying to run a custom P4 program (main.p4) on p4-dpdk-target.
bf_switchd successfully starts system services and loads the config file, but then terminates with:

bf_switchd: switch_config.c:252: switch_p4_pipeline_config_init: Assertion `mempool_obj_arr != NULL' failed.
Aborted

Even though ports.json contains "mempool_name": "MEMPOOL0", the pipeline initialization fails.

---

Environment

Component	Version / Details
OS	Ubuntu 24.04 (VM on VirtualBox)
P4-DPDK-Target	Latest build from GitHub (commit: )
SDE Install Dir	/home/p4/sde/install
Python	3.12 (virtualenv)
DPDK	Built automatically by p4-dpdk-target
Program	PSA → simple_l2l3_lpm.p4

---

Steps Performed

1. Set environment variables

export SDE=/home/p4/sde
export SDE_INSTALL=/home/p4/sde/install
export LD_LIBRARY_PATH=$SDE_INSTALL/lib:$SDE_INSTALL/lib64:$SDE_INSTALL/lib/x86_64-linux-gnu:$LD_LIBRARY_PATH
export PATH=$SDE_INSTALL/bin:$PATH

2. Launch bf_switchd

sudo -E PATH=$PATH LD_LIBRARY_PATH=$LD_LIBRARY_PATH \
    $SDE_INSTALL/bin/bf_switchd \
    --install-dir $SDE_INSTALL \
    --conf-file /home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/switchd.config

3. bf_switchd output

rm: cannot remove '/tmp/iospec.io': No such file or directory
bf_switchd_lib_init_local: Fail to delete /tmp/iospec.io file
bf_switchd: system services initialized
bf_switchd: loading conf_file .../switchd.config...
bf_switchd: processing device configuration...
  Family: dpdk
bf_switchd: processing P4 configuration...
bf_switchd: switch_config.c:252: switch_p4_pipeline_config_init: Assertion `mempool_obj_arr != NULL' failed.
Aborted

---

Directory Structure

sde/
 ├── install/
 └── p4-dpdk-target/
      └── examples/psa/simple_l2l3_lpm/
           ├── simple_l2l3_lpm.p4
           ├── simple_l2l3_lpm.bfrt.json
           ├── simple_l2l3_lpm.spec
           ├── context.json
           ├── ports.json
           └── switchd.config

---

Config Files Used

switchd.config

{
    "chip_list": [
        {
            "id": "asic-0",
            "chip_family": "dpdk",
            "instance": 0
        }
    ],
    "instance": 0,
"mempool": [
    {
        "name": "MEMPOOL0",
        "buffer_size": 2048,
        "num_buffers": 16384
    }
],

"p4_devices": [
    {
        "device-id": 0,
        "eal-args": "dummy -n 4 -c 7",
        "p4_programs": [
            {
                "program-name": "simple_l2l3_lpm",
                "sai_default_init": false,
                "bfrt-config": "/home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/simple_l2l3_lpm.bfrt.json",
                "port-config": "/home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/ports.json",
                "p4_pipelines": [
                    {
                        "p4_pipeline_name": "pipe",
                        "context": "/home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/context.json",
                        "config": "/home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/simple_l2l3_lpm.spec",
                        "pipe_scope": [0],
                        "path": "/home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm"
                    }
                ]
            }
        ]
    }
]

}

---

ports.json

{
    "ports": [
        {
            "dev_port": 0,
            "port_name": "TAP0",
            "mempool_name": "MEMPOOL0",
            "pipe_name": "pipe",
            "port_dir": "default",
            "port_in_id": 0,
            "port_out_id": 0,
            "port_type": "tap",
            "tap_port_attributes": {
                "mtu": 1500
            }
        }
    ]
}

---

Question / Request

bf_switchd fails with:

Assertion `mempool_obj_arr != NULL' failed.

Even though:

• mempool is defined in switchd.config

• mempool_name: "MEMPOOL0" is defined in ports.json

• config JSON and context JSON exist and are readable

Any guidance or an example for a minimal working PSA pipeline config for dpdk-target would be greatly appreciated.

---

@Dscano can you help with this once this programs work fine I have file to modify and add tables and then I can start writing the documentation

[Dscano]

Hi @Vineet1101

How did you obtain this switchd.config? I don't understand why, but your json seems differend from this one
https://github.com/p4lang/p4-dpdk-target?tab=readme-ov-file#config-file-used-by-bf_switchd.

Did you try using this JSON format from https://github.com/p4lang/p4-dpdk-target?tab=readme-ov-fileconfig-file-used-by-bf_switchd?

As you can see, the error that you get is related to Json parsing

p4-dpdk-target/bf_switchd/switch_config.c

Line 249 in 173c8a7

cJSON *mempool_obj_arr =

[Vineet1101]

thanks @Dscano it ran successfully

[Dscano]

thanks @Dscano it ran successfully

Great!

@Vineet1101, I suggest splitting your PR into two separate ones. First, focus on completing the current PR: #116. Once this is finalized, open a new PR to add commands for configuring the pipeline.

[Vineet1101]

So for #116 I should add details to install and run programs in p4-dpdk and in a new pr to modify tables am I correct???

[Dscano]

So for #116 I should add details to install and run programs in p4-dpdk and in a new pr to modify tables am I correct???

Yes, I suggest doing that because:

• We would like to have installation bash scripts, as Andy said Added guide to add table entries in P4 dpdk using native control plan… #116 (comment)
• It is easier to review.

[Vineet1101]

will do that

[Vineet1101]

@Dscano I am facing this error when starting the switch can you help with this

rm: cannot remove '/tmp/iospec.io': No such file or directory
bf_switchd_lib_init_local line:1716 Fail to delete /tmp/iospec.io file
Install dir: /home/p4/sde/install (0x58e6bb9fbcf0)
bf_switchd: system services initialized
bf_switchd: loading conf_file /home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/switchd.config...
bf_switchd: processing device configuration...
Configuration for dev_id 0
  Family        : dpdk
bf_switchd: processing P4 configuration...
P4 profile for dev_id 0
P4 EAL args dummy -n 4 -c 3
Debug CLI disable
num mempool objs 1
  mempool_name: MEMPOOL0
  buffer_size:  2304
  pool_size:    1024
  cache_size:   256
  numa_node:    0
num fixed functions 0
num P4 programs 1
  p4_name: simple_l2l3_lpm
  bfrt_config: /home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/simple_l2l3_lpm.bfrt.json
  port_config: /home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/ports.json
  p4_pipeline_name: pipe
  core_id: 1
  numa_node: 0
    context: /home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/simple_l2l3_lpm.context.json
    config: /home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/simple_l2l3_lpm.spec
  Pipes in scope [0 ]
  Timer values []
  Mirror Config
    n_slots: 4 
    n_sessions: 64 
    fast_clone: 0 
  diag: 
  accton diag: 
  non_default_port_ppgs: 0
  SAI default initialize: 1 
Operational mode set to DPDK MODEL
Initialized the device types using PAL handler registration
STUB:port_mgr_platform_init DPDK
bf_switchd: drivers initialized
EAL: Detected CPU lcores: 4
EAL: Detected NUMA nodes: 1
EAL: Detected shared linkage of DPDK
EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
EAL: Selected IOVA mode 'PA'
TELEMETRY: No legacy callbacks, legacy socket not created
2025-12-15 23:40:58.890288 BF_PIPE ERROR - ctx_json/ctx_json_utils.c:93: Invalid ContextJSON format: property "pipe_in" is not a string.
2025-12-15 23:40:58.890329 BF_PIPE ERROR - ctx_json/ctx_json_utils.c:93: Invalid ContextJSON format: property "pipe_out" is not a string.
2025-12-15 23:40:58.890346 BF_PORT ERROR - port_config_json_parse_ports:496: Failed to parse port from Port Config JSON
2025-12-15 23:40:58.890360 BF_PORT ERROR - parse_port_config_json:586: Failed to parse ports from Port Config JSON
2025-12-15 23:40:58.890380 BF_PORT ERROR - port_mgr_config_import : Error in parsing the port config file
2025-12-15 23:40:58.890411 BF_DVM ERROR - Device add handling failed for dev 0, sts No system resources (2), Client port_mgr 
2025-12-15 23:40:58.890427 BF_DVM ERROR - Device add failed for dev 0, sts No system resources (2)
ERROR: bf_device_add failed(2) for dev_id 0
ERROR: bf_switchd_device_add failed(2) for dev_id 0

bf_switchd: initialized 0 devices
bf_switchd_switchsai_lib_init
 starting SAI 
bf_switchd: spawning cli server thread
bf_switchd: spawning driver shell
bf_switchd: server started - listening on port 9999

        ********************************************
        *      WARNING: Authorised Access Only     *
        ********************************************
    

bfshell>

here is my ports.json file

{
    "ports": [
        {
            "dev_port": 0,
            "port_name": "TAP0",
            "mempool_name": "MEMPOOL0",
            "pipe_name": "pipe",
            "pipe_in": 0,
            "pipe_out": 0,
            "port_dir": "default",
            "port_in_id": 0,
            "port_out_id": 0,
            "port_type": "tap",
            "tap_port_attributes": { "mtu": 1500 }
        },
        {
            "dev_port": 1,
            "port_name": "TAP1",
            "mempool_name": "MEMPOOL0",
            "pipe_name": "pipe",
            "pipe_in": 0,
            "pipe_out": 0,
            "port_dir": "default",
            "port_in_id": 1,
            "port_out_id": 1,
            "port_type": "tap",
            "tap_port_attributes": { "mtu": 1500 }
        },
        {
            "dev_port": 2,
            "port_name": "TAP2",
            "mempool_name": "MEMPOOL0",
            "pipe_name": "pipe",
            "pipe_in": 0,
            "pipe_out": 0,
            "port_dir": "default",
            "port_in_id": 2,
            "port_out_id": 2,
            "port_type": "tap",
            "tap_port_attributes": { "mtu": 1500 }
        },
        {
            "dev_port": 3,
            "port_name": "TAP3",
            "mempool_name": "MEMPOOL0",
            "pipe_name": "pipe",
            "pipe_in": 0,
            "pipe_out": 0,
            "port_dir": "default",
            "port_in_id": 3,
            "port_out_id": 3,
            "port_type": "tap",
            "tap_port_attributes": { "mtu": 1500 }
        }
    ]
}

and switchd.config file

config
{
  "chip_list": [
    {
      "id": "asic-0",
      "chip_family": "dpdk",
      "instance": 0
    }
  ],
  "instance": 0,
  "p4_devices": [
    {
      "device-id": 0,
      "eal-args": "dummy -n 4 -c 3",

      "mempools": [
        {
          "name": "MEMPOOL0",
          "buffer_size": 2304,
          "pool_size": 1024,
          "cache_size": 256,
          "numa_node": 0
        }
      ],

      "p4_programs": [
        {
          "program-name": "simple_l2l3_lpm",
          "bfrt-config": "/home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/simple_l2l3_lpm.bfrt.json",
          "port-config": "/home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/ports.json",
          "p4_pipelines": [
            {
              "p4_pipeline_name": "pipe",
              "core_id": 1,
              "numa_node": 0,
              "context": "/home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/simple_l2l3_lpm.context.json",
              "config": "/home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm/simple_l2l3_lpm.spec",
              "pipe_scope": [
                0
              ],
              "path": "/home/p4/sde/p4-dpdk-target/examples/psa/simple_l2l3_lpm"
            }
          ]
        }
      ]
    }
  ]
}

[Dscano]

Does the switch work? What issue did you experience?

[Vineet1101]

the switch starts but when I ran tdi_python and then bfrt it shows bfrt is not defined

It is solved, sorry I pasted wrong path in switch file

[Vineet1101]

hey @Dscano I am trying to bulid p4-dpdk on new fresh Ubuntu22.04 vm and I facing this error. I have checked these files exists in the codebase still I am getting this error while building p4-dpdk
I am running these commands

cd $SDE/p4-dpdk-target && \
    git submodule update --init --recursive --force && \
    ./autogen.sh && \
    ./configure --prefix=$SDE_INSTALL && \
    make -j && \
    make install

[Dscano]

Hi @Vineet1101 ,

From the screenshot, it looks like libdpdk may not be installed on your OS. Could you please verify this? If it’s not installed, can you try installing it and see if that resolves the issue?

[swaroopsarma]

@Vineet1101 this error suggests that dpdk compilation is failed. DPDK is built part of this repo not used from system installation path

[Vineet1101]

@swaroopsarma this error was fixed i just needed to install libdpdk

[Vineet1101]

In [3]: dir(tdi.simple_l2l3_lpm)
Out[3]: 
['__call__',
 '__class__',
 '__delattr__',
 '__dict__',
 '__dir__',
 '__doc__',
 '__eq__',
 '__format__',
 '__ge__',
 '__getattribute__',
 '__gt__',
 '__hash__',
 '__init__',
 '__init_subclass__',
 '__le__',
 '__lt__',
 '__module__',
 '__ne__',
 '__new__',
 '__reduce__',
 '__reduce_ex__',
 '__repr__',
 '__setattr__',
 '__sizeof__',
 '__str__',
 '__subclasshook__',
 '__weakref__',
 '_add_child',
 '_children',
 '_cintf',
 '_commands',
 '_dep_tester',
 '_get_children',
 '_get_full_leaf_info',
 '_get_name',
 '_make_dep_tester_funcs',
 '_name',
 '_parent_node',
 '_set_doc',
 '_set_name',
 '_simple_tester',
 'clear',
 'dump',
 'info',
 'ip',
 'tdi_info']

In [4]: 

@Dscano @swaroopsarma I am getting this error when I am running dir(tdi.simple_l2l3_lpm) and there is no pipe field but according to this Readme I need to this

[Vineet1101]

Even when I try to run this pipe = tdi.<P4 program>.pipe.ingress command I am getting this error

In [2]: pipe=tdi.simple_l2l3_lpm.pipe.ingress
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-2-34d801f3f79a> in <module>
----> 1 pipe=tdi.simple_l2l3_lpm.pipe.ingress

AttributeError: 'TDINode' object has no attribute 'pipe'