> selftests/bpf: Cover fastcall helper stack reads
>
> Add verifier_bpf_fastcall test where a spill/fill pair initializes a stack
> slot. bpf_csum_diff() later reads it through ARG_PTR_TO_MEM | MEM_RDONLY.
>
> The translated program must keep the spill and fill materialized.
> Otherwise
> the helper reads stack bytes that no longer match the verifier model.
>
> Signed-off-by: Nuoqi Gui <[email protected]>
This test covers a fastcall spill/fill removal bug that the bpf_fastcall
spill/fill removal mechanism introduced in commit 5b5f51bff1b66
("bpf: no_caller_saved_registers attribute for helper calls").
Should this commit carry a Fixes: tag pointing at that commit?
Fixes: 5b5f51bff1b66 ("bpf: no_caller_saved_registers attribute for helper
calls")
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/28089002726
