Re: [PATCH v2] perf tools annotate: fix a crash when annotate the same symbol with 's' and 'T'

[James Clark <james.clark@linaro.org>]

On 15/10/2025 6:20 pm, Tianyou Li wrote:
> When perf report with annotation for a symbol, press 's' and 'T', then exit
> the annotate browser. Once annotate the same symbol, the annotate browser
> will crash.
> 
> The browser.arch was required to be correctly updated when data type
> feature was enabled by 'T'. Usually it was initialized by symbol__annotate2
> function. If a symbol has already been correctly annotated at the first
> time, it should not call the symbol__annotate2 function again, thus the
> browser.arch will not get initialized. Then at the second time to show the
> annotate browser, the data type needs to be displayed but the browser.arch
> is empty.
> 
> Stack trace as below:
> 
> Perf: Segmentation fault
> -------- backtrace --------
>      #0 0x55d365 in ui__signal_backtrace setup.c:0
>      #1 0x7f5ff1a3e930 in __restore_rt libc.so.6[3e930]
>      #2 0x570f08 in arch__is perf[570f08]
>      #3 0x562186 in annotate_get_insn_location perf[562186]
>      #4 0x562626 in __hist_entry__get_data_type annotate.c:0
>      #5 0x56476d in annotation_line__write perf[56476d]
>      #6 0x54e2db in annotate_browser__write annotate.c:0
>      #7 0x54d061 in ui_browser__list_head_refresh perf[54d061]
>      #8 0x54dc9e in annotate_browser__refresh annotate.c:0
>      #9 0x54c03d in __ui_browser__refresh browser.c:0
>      #10 0x54ccf8 in ui_browser__run perf[54ccf8]
>      #11 0x54eb92 in __hist_entry__tui_annotate perf[54eb92]
>      #12 0x552293 in do_annotate hists.c:0
>      #13 0x55941c in evsel__hists_browse hists.c:0
>      #14 0x55b00f in evlist__tui_browse_hists perf[55b00f]
>      #15 0x42ff02 in cmd_report perf[42ff02]
>      #16 0x494008 in run_builtin perf.c:0
>      #17 0x494305 in handle_internal_command perf.c:0
>      #18 0x410547 in main perf[410547]
>      #19 0x7f5ff1a295d0 in __libc_start_call_main libc.so.6[295d0]
>      #20 0x7f5ff1a29680 in __libc_start_main@@GLIBC_2.34 libc.so.6[29680]
>      #21 0x410b75 in _start perf[410b75]
> 
> Fixes: 1d4374afd000 ("perf annotate: Add 'T' hot key to toggle data type display")
> Reviewed-by: James Clark <james.clark@linaro.org>
> Signed-off-by: Tianyou Li <tianyou.li@intel.com>
> ---
>   tools/perf/ui/browsers/annotate.c | 3 +++
>   tools/perf/util/annotate.c        | 2 +-
>   tools/perf/util/annotate.h        | 2 ++
>   3 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/ui/browsers/annotate.c b/tools/perf/ui/browsers/annotate.c
> index 8fe699f98542..3b27ef1e8490 100644
> --- a/tools/perf/ui/browsers/annotate.c
> +++ b/tools/perf/ui/browsers/annotate.c
> @@ -1161,6 +1161,9 @@ int __hist_entry__tui_annotate(struct hist_entry *he, struct map_symbol *ms,
>   			if (!annotation__has_source(notes))
>   				ui__warning("Annotation has no source code.");
>   		}
> +	} else if (evsel__get_arch(evsel, &browser.arch)) {
> +		ui__error("Couldn't get architecture for event '%s'", evsel->name);
> +		return -1;
>   	}

symbol_annotate() only fails for negative return values of 
evsel__get_arch(), but evsel__get_arch() has at least two positive error 
return values.

If symbol_annotate() is wrong and it should be != 0 like you have, then 
maybe symbol_annotate() should be fixed in another commit in the same 
patchset as this one. Otherwise you have two calls to the same thing 
right next to each other that handle errors differently.

>   
>   	/* Copy necessary information when it's called from perf top */
> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> index a2e34f149a07..39d6594850f1 100644
> --- a/tools/perf/util/annotate.c
> +++ b/tools/perf/util/annotate.c
> @@ -980,7 +980,7 @@ void symbol__calc_percent(struct symbol *sym, struct evsel *evsel)
>   	annotation__calc_percent(notes, evsel, symbol__size(sym));
>   }
>   
> -static int evsel__get_arch(struct evsel *evsel, struct arch **parch)
> +int evsel__get_arch(struct evsel *evsel, struct arch **parch)
>   {
>   	struct perf_env *env = evsel__env(evsel);
>   	const char *arch_name = perf_env__arch(env);
> diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
> index eaf6c8aa7f47..d4990bff29a7 100644
> --- a/tools/perf/util/annotate.h
> +++ b/tools/perf/util/annotate.h
> @@ -585,4 +585,6 @@ void debuginfo_cache__delete(void);
>   int annotation_br_cntr_entry(char **str, int br_cntr_nr, u64 *br_cntr,
>   			     int num_aggr, struct evsel *evsel);
>   int annotation_br_cntr_abbr_list(char **str, struct evsel *evsel, bool header);
> +
> +int evsel__get_arch(struct evsel *evsel, struct arch **parch);
>   #endif	/* __PERF_ANNOTATE_H */