[PATCH] util: constant -1 with expression of type char and allocation failure handling

From: yskelg
Date: Wed Jun 19 2024 - 14:39:40 EST


From: Yunseong Kim <yskelg@xxxxxxxxx>

This patch resolve this warning.

tools/perf/util/evsel.c:1620:9: error: result of comparison of constant
-1 with expression of type 'char' is always false
-Werror,-Wtautological-constant-out-of-range-compare
1620 | if (c == -1)
| ~ ^ ~~

Add handling on unread_unwind_spec_debug_frame().
This make caller find_proc_info() works well when the allocation failure.

Signed-off-by: Yunseong Kim <yskelg@xxxxxxxxx>
---
tools/perf/util/evsel.c | 2 +-
tools/perf/util/unwind-libunwind-local.c | 5 +++++
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 25857894c047..bc603193c477 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1620,7 +1620,7 @@ static int evsel__read_group(struct evsel *leader, int cpu_map_idx, int thread)

static bool read_until_char(struct io *io, char e)
{
- char c;
+ int c;

do {
c = io__get_char(io);
diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
index cde267ea3e99..a424eae6d308 100644
--- a/tools/perf/util/unwind-libunwind-local.c
+++ b/tools/perf/util/unwind-libunwind-local.c
@@ -390,6 +390,11 @@ static int read_unwind_spec_debug_frame(struct dso *dso,
char *debuglink = malloc(PATH_MAX);
int ret = 0;

+ if (debuglink == NULL) {
+ pr_err("unwind: Can't read unwind spec debug frame.\n");
+ return -ENOMEM;
+ }
+
ret = dso__read_binary_type_filename(
dso, DSO_BINARY_TYPE__DEBUGLINK,
machine->root_dir, debuglink, PATH_MAX);
--
2.44.0