Re: [PATCH 4/5] perf symbol: Shrink the demangled Rust buffer to fit

[Namhyung Kim <namhyung@kernel.org>]

On Mon, Sep 28, 2026 at 02:02:26AM +0100, Michal Pluta wrote:
> The buffer a demangled Rust name is returned in is sized to whatever
> attempt succeeded, which is usually larger than the string it holds.
> Shrink it to the string's exact length before returning it.

Oh, you already have the patch! :)

Thanks,
Namhyung

> 
> Signed-off-by: Michal Pluta <michalpl2003@gmail.com>
> ---
>  tools/perf/util/symbol.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 1a52bc2980a0..858a14a91f79 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -2772,8 +2772,10 @@ char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
>  				break;
>  			demangled = tmp;
>  			if (rust_demangle_display_demangle(&rust_demangle, demangled, buf_len,
> -							   /*alternate=*/true) == OverflowOk)
> -				return demangled;
> +							   /*alternate=*/true) == OverflowOk) {
> +				tmp = realloc(demangled, strlen(demangled) + 1);
> +				return tmp ?: demangled;
> +			}
>  		}
>  		/* Failure to grow output buffer or buffer exceeded sensible bounds. */
>  		free(demangled);
> -- 
> 2.43.0
>