Failed to load eBPF byte-code on TAP device

[madhukar mythri <madhukar.mythri@gmail.com>]

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Hi all,

On the RHEL9.2 with DPDK 22.11.1 version, DPDK primary application failed
to add RSS flow on TAP sub-device, when loading the TAP BPF byte-code
instructions.

This "struct bpf_insn l3_l4_hash_insns[]" array(from file:
drivers/net/tap/tap_bpf_insns.h) is in eBPF bytecode instructions format,
this eBPF failed to load on TAP PMD with the following error:

=====================
rss_add_actions(): Failed to load BPF section 'l3_l4' (7): Argument list
too long.
net_failsafe: Failed to create a flow on sub_device 1."
=====================
On Kernel-version:  5.15.0 #9 SMP PREEMPT
Arch: x86_64 GNU/Linux

When added some debug logs on Kernel BPF verifier code, we could see that
instruction processed were reached to 1 Million.
But, the Byte code has only 1698 instructions only. Why the Kernel BPF
verifier is processing beyond 1,698 instructions ?

The same byte-code(with DPDK-22.11.1) worked well with RHEL8.x and not
working in RHEL-9.x version.

Does anybody faced such issues ?
Please let me know how to debug such issues on Byte-code.

Thanks,
Madhukar.

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