Re: [PATCH v4] perf tests: mmap-basic: fix user rdpmc detection logic

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Missing explicit inclusion of `<unistd.h>` for POSIX libc functions.
--

--- Patch [1]: [PATCH v4] perf tests: mmap-basic: fix user rdpmc detection logic ---
commit 4b703a4e5dfd0ba3b4f770b8ec3924ee647f0a6c
Author: Qiao Zhao <qzhao@redhat.com>

perf tests: mmap-basic: fix user rdpmc detection logic

This patch introduces a fallback to /proc/sys/kernel/perf_user_access for 
RISC-V and Arm to control userspace counter access in the mmap-basic test. 
It also updates the test logic to support restoring arbitrary values and 
adjusts expectations for Arm platforms.

> diff --git a/tools/perf/tests/mmap-basic.c b/tools/perf/tests/mmap-basic.c
> index 5cec7644952c7..4433a5df3d776 100644
> --- a/tools/perf/tests/mmap-basic.c
> +++ b/tools/perf/tests/mmap-basic.c
[ ... ]
> @@ -182,47 +183,77 @@ static int test__basic_mmap(struct test_suite *test __maybe_unused, int subtest
>  }
>  
>  enum user_read_state {
[ ... ]
> +static int set_user_read_fd(int fd, int enabled)
>  {
[ ... ]
> +	if (enabled == old_user_read)
> +		return old_user_read;
> +
> +	len = scnprintf(buf, sizeof(buf), "%d\n", enabled);
> +	if (lseek(fd, 0, SEEK_SET) < 0) {

[Severity: Low]
Does this code build correctly with musl libc?

This patch introduces lseek() and SEEK_SET in set_user_read_fd(), but there
is no explicit include for <unistd.h>. While it currently compiles under
glibc due to implicit includes, relying on this can cause build failures
under musl libc where headers are strictly separated.

Could <unistd.h> be explicitly included alongside the other headers?

> +		pr_debug("%s seek failed\n", __func__);
> +		return old_user_read;
>  	}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260817-rdpmc-detection-logic-v4-1-c22074578f6a@linaro.org?part=1