Re: [PATCH] perf unwind: handle allocation failure in libdw__get_entries()

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Memory leak of `ui` structure upon `dwfl_ui_ti` allocation failure.
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--- Patch [1]: [PATCH] perf unwind: handle allocation failure in libdw__get_entries() ---
commit cfa13e49d271d0f1a99af3ba9b78fd579579b1d0
Author: Triet Hoang <[email protected]>

perf unwind: handle allocation failure in libdw__get_entries()

This commit adds a return value check for zalloc() when allocating the
dwfl_ui_ti structure. It returns -ENOMEM upon failure to avoid a NULL
pointer dereference.

> diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
> index 7f35042be5677..ff36552ca1759 100644
> --- a/tools/perf/util/unwind-libdw.c
> +++ b/tools/perf/util/unwind-libdw.c
[ ... ]
> @@ -379,6 +379,9 @@ int libdw__get_entries(unwind_entry_cb_t cb, void *arg,
>  		dwfl = dwfl_ui_ti->dwfl;
>  	} else {
>  		dwfl_ui_ti = zalloc(sizeof(*dwfl_ui_ti));
> +		if (!dwfl_ui_ti)
> +			return -ENOMEM;

[Severity: Medium]
Does this code leak the previously allocated ui structure?

Earlier in libdw__get_entries(), ui is allocated with:

    ui = zalloc(sizeof(*ui) + sizeof(ui->entries[0]) * max_stack);

Returning directly here bypasses the cleanup path at the out label, which
normally calls free(ui). Should we free the ui structure before returning
-ENOMEM?

> +
>  		dwfl = dwfl_begin(&offline_callbacks);
>  		if (!dwfl)
>  			goto out;

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=1