perf annotate: Fix segfault on sample histogram

A symbol can have no samples, then accessing the annotated_source->samples
hashmap will result in a segfault.

Fixes: a3f7768 ("perf annotate: Fix memory leak in annotated_source")
Reviewed-by: Ian Rogers <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: namhyung

tools/perf/util/annotate.c

@@ -113,10 +113,11 @@ static __maybe_unused void annotated_source__delete(struct annotated_source *src
 	if (src == NULL)
 		return;
 
-	hashmap__for_each_entry(src->samples, cur, bkt)
-		zfree(&cur->pvalue);
-
-	hashmap__free(src->samples);
+	if (src->samples) {
+		hashmap__for_each_entry(src->samples, cur, bkt)
+			zfree(&cur->pvalue);
+		hashmap__free(src->samples);
+	}
 	zfree(&src->histograms);
 	free(src);
 }