Re: [PATCH v2 4/6] perf kvm: Do not copy filename string

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The error checking logic for `get_filename_for_perf_kvm()` is unreachable dead code.
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commit 0b8de0bac81d07f5d9beff7d22b8144187910bab
Author: Namhyung Kim <namhyung@kernel.org>

perf kvm: Do not copy filename string

As it removed STRDUP_FAIL_EXIT(), it no longer calls free() for elements
in the copied argv.  Thus, the filename should not be allocated as well.
In fact, it's a pointer to string literals and should be fine to pass
the pointer.

> diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
> index 278543ca66a37..021af3c64acd0 100644
> --- a/tools/perf/builtin-kvm.c
> +++ b/tools/perf/builtin-kvm.c
> @@ -607,11 +607,11 @@ static const char *get_filename_for_perf_kvm(void)
>  	const char *filename;
>  
>  	if (perf_host && !perf_guest)
> -		filename = strdup("perf.data.host");
> +		filename = "perf.data.host";
>  	else if (!perf_host && perf_guest)
> -		filename = strdup("perf.data.guest");
> +		filename = "perf.data.guest";
>  	else
> -		filename = strdup("perf.data.kvm");
> +		filename = "perf.data.kvm";
>  
>  	return filename;
>  }

[Severity: Low]
Does this change leave unreachable dead code in cmd_kvm()?

Now that get_filename_for_perf_kvm() returns static string literals, it can
never return NULL. However, its caller cmd_kvm() still checks for NULL and
returns -ENOMEM:

	if (!file_name) {
		file_name = get_filename_for_perf_kvm();

		if (!file_name) {
			pr_err("Failed to allocate memory for filename\n");
			return -ENOMEM;
		}
	}

Is it okay to clean up the redundant NULL check and error message from
cmd_kvm() since this allocation failure is no longer possible?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260623191439.3621593-1-namhyung@kernel.org?part=4