[PATCH v3 3/3] kasan: use stack_trace_save_shadow

[andrey.konovalov@linux.dev]

From: Andrey Konovalov <andreyknvl@google.com>

Use stack_trace_save_shadow() to collect stack traces whenever
CONFIG_HAVE_SHADOW_STACKTRACE is enabled. This improves the
boot time of a defconfig build by ~30% for all KASAN modes.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/kasan/common.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 23b30fa6e270..00fef2e5fe90 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -97,7 +97,9 @@ depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc)
 	unsigned long entries[KASAN_STACK_DEPTH];
 	unsigned int nr_entries;
 
-	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
+	nr_entries = stack_trace_save_shadow(entries, ARRAY_SIZE(entries));
+	if (nr_entries < 0)
+		nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
 	return __stack_depot_save(entries, nr_entries, flags, can_alloc);
 }
 
-- 
2.25.1