Re: [PATCH v3 3/7] perf probe: Do not show non representive lines by perf-probe -L

From: Arnaldo Carvalho de Melo
Date: Mon Nov 18 2019 - 17:01:52 EST


Em Mon, Nov 18, 2019 at 05:12:10PM +0900, Masami Hiramatsu escreveu:
> Since perf probe -L shows non representive lines, it can be
> mislead users where user can put probes.
> This prevents to show such non representive lines so that user
> can understand which lines user can probe.
>
> # perf probe -L kernel_read
> <kernel_read@/build/linux-pvZVvI/linux-5.0.0/fs/read_write.c:0>
> 0 ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
> {
> 2 mm_segment_t old_fs;
> ssize_t result;
>
> old_fs = get_fs();
> 6 set_fs(get_ds());
> /* The cast to a user pointer is valid due to the set_fs() */
> 8 result = vfs_read(file, (void __user *)buf, count, pos);
> 9 set_fs(old_fs);
> 10 return result;
> }
> EXPORT_SYMBOL(kernel_read);

Thanks, this fixes the problem I reported, applied.

- Arnaldo

> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> ---
> tools/perf/util/probe-finder.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index ef1b320cedf8..f12ad507a822 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -1734,12 +1734,19 @@ static int line_range_walk_cb(const char *fname, int lineno,
> void *data)
> {
> struct line_finder *lf = data;
> + const char *__fname;
> + int __lineno;
> int err;
>
> if ((strtailcmp(fname, lf->fname) != 0) ||
> (lf->lno_s > lineno || lf->lno_e < lineno))
> return 0;
>
> + /* Make sure this line can be reversable */
> + if (cu_find_lineinfo(&lf->cu_die, addr, &__fname, &__lineno) > 0
> + && (lineno != __lineno || strcmp(fname, __fname)))
> + return 0;
> +
> err = line_range_add_line(fname, lineno, lf->lr);
> if (err < 0 && err != -EEXIST)
> return err;

--

- Arnaldo