perf python: Avoid 2 leak sanitizer issues

Leak sanitizer complains about the variable size bf allocation and
store to bf if sized 0.

Signed-off-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ali Saidi <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Athira Rajeev <[email protected]>
Cc: Brian Robbins <[email protected]>
Cc: Changbin Du <[email protected]>
Cc: Dmitrii Dolgov <[email protected]>
Cc: Fangrui Song <[email protected]>
Cc: German Gomez <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Ivan Babrou <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jing Zhang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: K Prateek Nayak <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Liam Howlett <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Miguel Ojeda <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: Steinar H. Gunderson <[email protected]>
Cc: Suzuki Poulouse <[email protected]>
Cc: Wenyu Liu <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yang Jihong <[email protected]>
Cc: Ye Xingchen <[email protected]>
Cc: Yuan Can <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/perf/util/scripting-engines/trace-event-python.c

@@ -735,6 +735,9 @@ static void regs_map(struct regs_dump *regs, uint64_t mask, const char *arch, ch
 	unsigned int i = 0, r;
 	int printed = 0;
 
+	if (size <= 0)
+		return;
+
 	bf[0] = 0;
 
 	if (!regs || !regs->regs)
@@ -764,7 +767,7 @@ static void set_regs_in_dict(PyObject *dict,
 	 * 10 chars is for register name.
 	 */
 	int size = __sw_hweight64(attr->sample_regs_intr) * 28;
-	char bf[size];
+	char *bf = malloc(size);
 
 	regs_map(&sample->intr_regs, attr->sample_regs_intr, arch, bf, sizeof(bf));
 
@@ -775,6 +778,7 @@ static void set_regs_in_dict(PyObject *dict,
 
 	pydict_set_item_string_decref(dict, "uregs",
 			_PyUnicode_FromString(bf));
+	free(bf);
 }
 
 static void set_sym_in_dict(PyObject *dict, struct addr_location *al,