Re: [PATCH v4 3/6] perf libdw: Fix libdw API contract violations

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Missing O_NONBLOCK when opening dso_name in dso__libdw_dwfl()
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commit 95f9f15ab79b0136da9eb501da82453ee78787c1
Author: Ian Rogers <irogers@google.com>

perf libdw: Fix libdw API contract violations

This commit adds error checking for dwfl_report_end and dwfl_module_addrdie.
It also introduces inline_node__clear_frames() to clean up partial allocations
and fixes potential memory leaks in libdw__addr2line().

> diff --git a/tools/perf/util/libdw.c b/tools/perf/util/libdw.c
> index 216977884103..e69ff4cea856 100644
> --- a/tools/perf/util/libdw.c
> +++ b/tools/perf/util/libdw.c
[ ... ]
> @@ -60,7 +61,11 @@ struct Dwfl *dso__libdw_dwfl(struct dso *dso)
>  		return NULL;
>  	}
>  
> -	dwfl_report_end(dwfl, /*removed=*/NULL, /*arg=*/NULL);
> +	if (dwfl_report_end(dwfl, NULL, NULL) != 0) {
> +		dwfl_end(dwfl);
> +		return NULL;
> +	}
> +
>  	dso__set_libdw(dso, dwfl);
>  
>  	return dwfl;

This isn't a bug introduced by this commit, but since this function is being
updated, could we also look at the open() call earlier in dso__libdw_dwfl()?

dso__libdw_dwfl() calls:
    fd = open(dso_name, O_RDONLY);

If dso_name originates from user-controlled mmap events, it might point to a
FIFO, character device, or a hanging network mount.

Could this open() hang indefinitely?

Would it be safer to include the O_NONBLOCK flag here?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260503171032.1559338-1-irogers@google.com?part=3