dpdk/eal: fix secondary process resetting NIC via eal_bus_cleanup()

[jfb8856606]

Problem

When a secondary DPDK process exits (e.g. ff_ifconfig, ff_sysctl), the primary process (F-Stack/nginx) stops accepting new connections. The NIC becomes non-functional until the primary process is restarted.

Reproduction:

# Start F-Stack primary process (nginx)
./nginx ...

# Run any f-stack tool (even just --help triggers the bug)
./ff_ifconfig --help   # primary stops receiving packets after this returns

Root Cause

DPDK commit 1cab1a40ea9b ("bus: cleanup devices on shutdown", introduced in DPDK 22.11) added eal_bus_cleanup() to rte_eal_cleanup() without distinguishing between primary and secondary processes.

When rte_eal_cleanup() is called in the secondary process, it executes:

rte_mp_channel_cleanup()    <- closes IPC socket
eal_bus_cleanup()           <- calls drv->remove() on ALL PCI devices
  -> pci_cleanup()
  -> drv->remove(dev)       <- eth_virtio_pci_remove()
  -> virtio_dev_close()
  -> virtio_reset(hw)       <- writes 0x00 to VIRTIO_CONFIG_STATUS_RESET !

virtio_reset() performs a full hardware reset of the NIC. The primary process still holds the device but its hardware state has been destroyed.

Fix

Guard eal_bus_cleanup() with a primary-process check so secondary processes skip the bus cleanup:

if (rte_eal_process_type() == RTE_PROC_PRIMARY)
    eal_bus_cleanup();

This is consistent with the fix in upstream DPDK commit 4bc53f8f0d64 ("eal: fix MP socket cleanup"), which was merged for DPDK 25.07. The upstream fix also reorders eal_bus_cleanup() before rte_mp_channel_cleanup() to handle IPC-dependent cleanup in drivers; this backport takes the simpler approach of skipping bus cleanup in secondary processes entirely.

Affected Versions

All DPDK LTS releases that include commit 1cab1a40ea9b are affected:

• DPDK 22.11.x (all point releases)
• DPDK 23.11.x (including F-Stack bundled 23.11.5)
• DPDK 24.11.x (up to at least 24.11.4)

The fix is available in DPDK 25.07+ only.

References

• Issue: Executing any of tools (ifconfig, netstat, ipfw) breaks running primary process #860
• Upstream fix: DPDK commit 4bc53f8f0d64 ("eal: fix MP socket cleanup", 2025-07-19)
• Bug-introducing commit: 1cab1a40ea9b ("bus: cleanup devices on shutdown", 2022-10-04)