Re: [PATCH v1 1/2] perf libdw: Fix Dwfl discovery with split files

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Early error return in `cmd__addr2line` leaves the addr2line subprocess pipe in a dirty state, corrupting subsequent IPC queries.
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commit 15f52b88a78ae8721f4ec48695f230d6450c86f6
Author: Ian Rogers <irogers@google.com>

perf libdw: Fix Dwfl discovery with split files

This patch dynamically frees the cached Dwfl object and alternative a2l
caches whenever a newly discovered split-debug file is assigned to a
dso, and scopes accessors behind a mutex.

> diff --git a/tools/perf/util/addr2line.c b/tools/perf/util/addr2line.c
> index 4b0d349ed334b..7c7eea3cc8dd2 100644
> --- a/tools/perf/util/addr2line.c
> +++ b/tools/perf/util/addr2line.c
[ ... ]
> @@ -414,12 +426,21 @@ int cmd__addr2line(const char *dso_name, u64 addr,
>  	}
>  
>  out:
> +	mutex_lock(dso__lock(dso));
>  	free(record_function);
>  	free(record_filename);
> -	if (io.eof) {
> -		dso__set_a2l(dso, NULL);
> +
> +	current_dso_name = dso__symsrc_filename(dso) ?: dso__long_name(dso);
> +	if (!io.eof && dso__a2l(dso) == NULL && current_dso_name &&
> +	    !strcmp(current_dso_name, dso_name))
> +		dso__set_a2l(dso, a2l);

[Severity: High]
This is a pre-existing issue, but an early error return in cmd__addr2line()
(such as a memory allocation failure when calling inline_list__append_record()
or a parsing failure in read_addr2line_record()) aborts the read loop and
jumps here without consuming the rest of the IPC stream.

Since EOF is not reached during an early abort, does this incorrectly
restore the dirty subprocess pipe back into the cache? It appears this
leaves unread output in the pipe, which could corrupt subsequent address
resolutions for this DSO when other threads query it and read the
leftover garbage data.

> +	else
>  		addr2line_subprocess_cleanup(a2l);
> -	}
> +	mutex_unlock(dso__lock(dso));
> +	return ret;
> +
> +out_unlock:
> +	mutex_unlock(dso__lock(dso));
>  	return ret;
>  }

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Sashiko AI review · https://sashiko.dev/#/patchset/20260914170759.1992947-1-irogers@google.com?part=1