Re: [PATCH v9 14/18] perf env: Refactor perf_env__arch_strerrno

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Cross-architecture analysis regression in errno string decoding for global system summaries.
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commit db5c373c1c19f2552fd69fd048980560d992a842
Author: Ian Rogers <irogers@google.com>

perf env: Refactor perf_env__arch_strerrno

This commit modifies perf_env__arch_strerrno to take an e_machine constant
instead of an architecture string and updates callers in builtin-trace.c.
It also adds a helper script to map Linux directory names to ELF machine
constants.

> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index e58c49d047a2..d278af18542f 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
[ ... ]
> @@ -4890,7 +4889,9 @@ static size_t syscall__dump_stats(struct trace *trace, int e_machine, FILE *fp,
>  
>  				for (e = 0; e < stats->max_errno; ++e) {
>  					if (stats->errnos[e] != 0)
> -						fprintf(fp, "\t\t\t\t%s: %d\n", perf_env__arch_strerrno(trace->host->env, e + 1), stats->errnos[e]);
> +						fprintf(fp, "\t\t\t\t%s: %d\n",
> +							perf_env__arch_strerrno(e_machine, e + 1),
> +							stats->errnos[e]);
>  				}
>  			}
>  			lines++;

How does this impact cross-architecture analysis for global system summaries?

Prior to this patch, syscall__dump_stats() used the target environment 
(trace->host->env) to decode errno strings.

By switching to the e_machine argument, if the caller for global system
summaries passes a hardcoded EM_HOST (or an equivalent host-specific
default), will cross-architecture global summaries now incorrectly decode
errnos using the host architecture's mappings instead of the target's?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260503002248.1040791-1-irogers@google.com?part=14