Re: [PATCH v9] perf evsel: Find process with busy PMUs for EBUSY

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] perf: missing POSIX header inclusions for libc functions
--

commit d5be35562f4cbefd7876eec8560215b17ee34b81
Author: Chun-Tse Shao <ctshao@google.com>

perf evsel: Find process with busy PMUs for EBUSY

This commit parses fdinfo with PMU type, comparing it with the event which
failed to open, and reports the processes causing EBUSY errors.

> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index d4cb455f4a7d4..e6d67d522ebf3 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c

[ ... ]

> @@ -4288,12 +4300,51 @@ static int dump_perf_event_processes(char *msg, size_t size)

[ ... ]

> +			/* Let's check the PMU type reserved by this process */
> +			scnprintf(buf, sizeof(buf), "%s/fdinfo/%s",
> +				  proc_entry->d_name, fd_entry->d_name);
> +			fdinfo_fd = openat(dirfd(proc_dir), buf, O_RDONLY | O_NONBLOCK);

[Severity: Low]
Will this compile under musl libc without explicitly including <fcntl.h> for
openat and O_NONBLOCK, as well as <unistd.h> for read and close?

> +			if (fdinfo_fd == -1)
> +				continue;
> +			fdinfo_size = read(fdinfo_fd, fdinfo_buf, sizeof(fdinfo_buf) - 1);
> +			close(fdinfo_fd);
> +			if (fdinfo_size < 0)
> +				continue;
> +			fdinfo_buf[fdinfo_size] = '\0';
> +
> +			line = strtok_r(fdinfo_buf, "\n", &saveptr);
> +			while (line) {
> +				if (sscanf(line,

[Severity: Low]
Does this require <stdio.h> to be explicitly included for sscanf to prevent
musl libc build failures?

> +					   "perf_event_attr.type:\t%u",
> +					   &perf_event_type) == 1) {
> +					/* continue parsing */
> +				} else if (sscanf(line,
> +						  "pmu_type:\t%u",
> +						  &pmu_type) == 1) {
> +					/* continue parsing */
> +				}
> +				line = strtok_r(NULL, "\n", &saveptr);
> +			}

[ ... ]

> @@ -4304,10 +4355,12 @@ static int dump_perf_event_processes(char *msg, size_t size)
>  				for (ssize_t i = 0; i < cmdline_size; i++) {
>  					if (buf[i] == '\0')
>  						buf[i] = ' ';
> +					else if (!isprint((unsigned char)buf[i]))

[Severity: Low]
Does this require <ctype.h> to be explicitly included for isprint to ensure
compatibility with musl libc builds?

> +						buf[i] = '.';
>  				}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260915204951.2935261-2-ctshao@google.com?part=1