Re: [PATCH v7 2/6] perf ui hists: Guard against NULL hist_entry in add_script_opt()

[sashiko-bot@kernel.org]

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

Pre-existing issues:
- [High] NULL pointer dereference when toggling annotation with an empty browser selection.
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--- Patch [2]: [PATCH v7 2/6] perf ui hists: Guard against NULL hist_entry in add_script_opt() ---
commit f95ba72ff3ba56daab82a876b00253253abac4da
Author: Ian Rogers <irogers@google.com>

perf ui hists: Guard against NULL hist_entry in add_script_opt()

This commit adds an explicit check for a NULL hist_entry in add_script_opt()
before accessing the entry's time field. This prevents a potential NULL
pointer dereference when the browser selection is empty or filtered out.

While reviewing this fix, I noticed a similar pre-existing issue in another
file.

tools/perf/builtin-c2c.c:perf_c2c__toggle_annotation()
> static int perf_c2c__toggle_annotation(struct hist_browser *browser)
> {
> 	struct hist_entry *he = browser->he_selection;
> 	// ...
> 	if (!perf_c2c__has_annotation(he->hists->hpp_list)) {

[Severity: High]
This is a pre-existing issue, but could this cause a segmentation fault if
the browser selection is empty? The code dereferences the he pointer to
access he->hists->hpp_list before validating it.

> 		ui_browser__help_window(&browser->b, "No annotation support");
> 		return 0;
> 	}
> 
> 	if (he == NULL) {

If a user opens the c2c cacheline browser on an empty or completely
filtered dataset and presses the annotation hotkey, browser->he_selection 
is NULL. Since the safety check happens after the dereference, it appears 
this would crash the perf tool.

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Sashiko AI review · https://sashiko.dev/#/patchset/20260723045949.988740-1-irogers@google.com?part=2