Re: [PATCH v1 1/4] perf find-map: Remove PATH_MAX 128-byte stack array restriction

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The `read_ret` variable is assigned the result of `getline()` but is never subsequently used, which triggers a `-Wunused-but-set-variable` compilation error.
--

--- Patch [1]: [PATCH v1 1/4] perf find-map: Remove PATH_MAX 128-byte stack array restriction ---
commit 9da3c5d9150546a40fb376c8547c0725fc587af7
Author: Ian Rogers <irogers@google.com>
perf find-map: Remove PATH_MAX 128-byte stack array restriction

This commit updates the find_map function to dynamically allocate the 
line buffer using getline. This prevents potential buffer overruns 
associated with the previous 128-byte stack array limitation.

> diff --git a/tools/perf/util/find-map.c b/tools/perf/util/find-map.c
> index 7b2300588ece0..4d740b32814f8 100644
> --- a/tools/perf/util/find-map.c
> +++ b/tools/perf/util/find-map.c
[ ... ]
> @@ -1,8 +1,14 @@
>  // SPDX-License-Identifier: GPL-2.0
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +
>  static int find_map(void **start, void **end, const char *name)
>  {
>  	FILE *maps;
> -	char line[128];
> +	char *line = NULL;
> +	size_t len = 0;
> +	ssize_t read_ret;
>  	int found = 0;
>  
>  	maps = fopen("/proc/self/maps", "r");
> @@ -11,7 +17,7 @@ static int find_map(void **start, void **end, const char *name)
>  		return -1;
>  	}
>  
> -	while (!found && fgets(line, sizeof(line), maps)) {
> +	while (!found && (read_ret = getline(&line, &len, maps)) != -1) {

[Severity: Low]
Does this leave the read_ret variable set but never used?

Because perf is typically built with -Werror, this unused assignment
triggers a -Wunused-but-set-variable compiler warning which gets promoted
to a build failure. 

Could the read_ret variable be removed and the loop condition simplified to 
just evaluate getline(&line, &len, maps) != -1 directly?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260720175455.3645946-1-irogers@google.com?part=1