Re: [PATCH v3 16/17] perf maps: Fix lock inversion in maps__load_first() and bounds check in __maps__remove()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] perf: missing <string.h> inclusion for string operations
--

commit ea7ae95649777ad210584a0f4110f0b3b715c591
Author: Ian Rogers <irogers@google.com>

perf maps: Fix lock inversion in maps__load_first() and bounds check in __maps__remove()

This commit addresses a read-to-write self-deadlock in maps__load_first()
and adds bounds checking in __maps__remove() to handle concurrent map
removals.

> diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
> index f808df2fe77b4..c0fccb776bede 100644
> --- a/tools/perf/util/maps.c
> +++ b/tools/perf/util/maps.c

[ ... ]

> @@ -556,10 +558,14 @@ static void __maps__remove(struct maps *maps, struct map *map)
>  	if (maps_by_name) {
>  		unsigned int name_idx = maps__by_name_index(maps, map);
>  
> -		map__put(maps_by_name[name_idx]);
> -		memmove(&maps_by_name[name_idx],
> -			&maps_by_name[name_idx + 1],
> -			(nr_maps - name_idx - 1) *  sizeof(*maps_by_name));
> +		if (name_idx < nr_maps) {
> +			map__put(maps_by_name[name_idx]);
> +			memmove(&maps_by_name[name_idx],
> +				&maps_by_name[name_idx + 1],
> +				(nr_maps - name_idx - 1) * sizeof(*maps_by_name));

[Severity: Low]
Does this file need an explicit #include <string.h>?

The perf subsystem guidelines require developers to explicitly include the
POSIX-specified headers for any libc functions used (specifically citing
<string.h>) to ensure musl compatibility.

This file invokes memmove() but lacks an explicit #include <string.h>. Since
the patch directly modifies a block invoking memmove() without adding the
requisite header, could this cause build failures on musl libc where standard
headers are not implicitly included?

> +		} else {
> +			__maps__free_maps_by_name(maps);
> +		}
>  	}
>  
>  	--RC_CHK_ACCESS(maps)->nr_maps;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261016173106.679725-1-irogers@google.com?part=16