From: James Clark <james.clark@arm.com>
Date: Fri, 30 Jun 2023 16:38:39 +0100
Subject: perf symbol: Fix uninitialized return value in
 symbols__find_by_name()
Git-commit: 78a175c4623f66722709494295a0f6754b46f858
Patch-mainline: v6.5-rc1
References: perf-v6.7 (jsc#PED-6012 jsc#PED-6121)

found_idx and s aren't initialized, so if no symbol is found then the
assert at the end will index off the end of the array causing a
segfault. The function also doesn't return NULL when the symbol isn't
found even if the assert passes. Fix it by initializing the values and
only setting them when something is found.

Fixes the following test failure:

  $ perf test 1
  1: vmlinux symtab matches kallsyms     : FAILED!

Fixes: 259dce914e93 ("perf symbol: Remove symbol_name_rb_node")
Signed-off-by: James Clark <james.clark@arm.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/r/20230630153840.858668-1-james.clark@arm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Tony Jones <tonyj@suse.de>
---
 tools/perf/util/symbol.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index bc79291b9f3b..f849f9ef68e6 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -495,7 +495,10 @@ static struct symbol *symbols__find_by_name(struct symbol *symbols[],
 					    size_t *found_idx)
 {
 	size_t i, lower = 0, upper = symbols_len;
-	struct symbol *s;
+	struct symbol *s = NULL;
+
+	if (found_idx)
+		*found_idx = SIZE_MAX;
 
 	if (!symbols_len)
 		return NULL;
@@ -504,8 +507,7 @@ static struct symbol *symbols__find_by_name(struct symbol *symbols[],
 		int cmp;
 
 		i = (lower + upper) / 2;
-		s = symbols[i];
-		cmp = symbol__match_symbol_name(s->name, name, includes);
+		cmp = symbol__match_symbol_name(symbols[i]->name, name, includes);
 
 		if (cmp > 0)
 			upper = i;
@@ -514,10 +516,11 @@ static struct symbol *symbols__find_by_name(struct symbol *symbols[],
 		else {
 			if (found_idx)
 				*found_idx = i;
+			s = symbols[i];
 			break;
 		}
 	}
-	if (includes != SYMBOL_TAG_INCLUDE__DEFAULT_ONLY) {
+	if (s && includes != SYMBOL_TAG_INCLUDE__DEFAULT_ONLY) {
 		/* return first symbol that has same name (if any) */
 		for (; i > 0; i--) {
 			struct symbol *tmp = symbols[i - 1];
@@ -525,13 +528,12 @@ static struct symbol *symbols__find_by_name(struct symbol *symbols[],
 			if (!arch__compare_symbol_names(tmp->name, s->name)) {
 				if (found_idx)
 					*found_idx = i - 1;
+				s = tmp;
 			} else
 				break;
-
-			s = tmp;
 		}
 	}
-	assert(!found_idx || s == symbols[*found_idx]);
+	assert(!found_idx || !s || s == symbols[*found_idx]);
 	return s;
 }