Re: [PATCH bpf-next 1/2] selftests/bpf: Return the lock error from buddy_init() of libarena

[bot+bpf-ci]

> selftests/bpf: Return the lock error from buddy_init() of libarena

TL;DR: Commit message only: the Fixes: tag may point at the wrong commit
(b1487dc1b181, which doesn't touch buddy_init()); 86426a28c52d introduced the
code being changed.

>     selftests/bpf: Return the lock error from buddy_init() of libarena
>
>     buddy_init() takes the buddy lock, an arena spin lock, to put its first
>     chunk on the list, and returns -EINVAL when it can't.
>     arena_spin_lock() fails with -EOPNOTSUPP on kernels built with more
>     than 1024 possible CPUs, where it has no queue node for every CPU, and
>     with -ETIMEDOUT or -EBUSY otherwise. Returning -EINVAL for all of them
>     hides which one happened from the caller.
>     Return the error of the lock.
>     Fixes: b1487dc1b181 ("selftests/bpf: Add selftests for libarena buddy allocator")
>     Signed-off-by: Qiliang Yuan <odys.yuan@xxxxxxxxx>

Is the Fixes: tag pointing at the right commit?

b1487dc1b181 ("selftests/bpf: Add selftests for libarena buddy allocator")
only adds st_buddy.bpf.c, st_asan_buddy.bpf.c, prog_tests/libarena.c and
prog_tests/libarena_asan.c.  It does not touch src/buddy.bpf.c or
buddy_init().

The code being changed here:

    if (buddy_lock(buddy, flags)) {
        bpf_arena_free_pages(&arena, chunk, BUDDY_CHUNK_PAGES);
        return -EINVAL;
    }

was introduced by 86426a28c52d ("selftests/bpf: Add buddy allocator for
libarena"), which added buddy.bpf.c with buddy_init() already returning
-EINVAL when buddy_lock() failed.  The selftests commit only exposes the
discarded error, it did not introduce the code that discards it.

The same tag is also used by the follow-up commit 27aeee1ef85a
("selftests/bpf: Skip libarena on kernels with too many possible CPUs"),
which depends on this patch to see -EOPNOTSUPP from arena_buddy_reset().

Should this be:

  Fixes: 86426a28c52d ("selftests/bpf: Add buddy allocator for libarena")


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