The never-taken branch leads to an invalid bounds condition, which is by
design. To avoid the unwanted warning from the compiler, hide the
variable from the optimizer.
../lib/stackinit_kunit.c: In function 'do_nothing_u16_zero':
../lib/stackinit_kunit.c:51:49: error: array subscript 1 is outside array
bounds of 'u16[0]' {aka 'short unsigned int[]'} [-Werror=array-bounds=]
51 | #define DO_NOTHING_RETURN_SCALAR(ptr) *(ptr)
| ^~~~~~
../lib/stackinit_kunit.c:219:24: note: in expansion of macro
'DO_NOTHING_RETURN_SCALAR'
219 | return DO_NOTHING_RETURN_ ## which(ptr + 1); \
| ^~~~~~~~~~~~~~~~~~
Signed-off-by: Kees Cook <[email protected]>
---
lib/stackinit_kunit.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/lib/stackinit_kunit.c b/lib/stackinit_kunit.c
index c14c6f8e6308..c40818ec9c18 100644
--- a/lib/stackinit_kunit.c
+++ b/lib/stackinit_kunit.c
@@ -212,6 +212,7 @@ static noinline void test_ ## name (struct kunit *test)
\
static noinline DO_NOTHING_TYPE_ ## which(var_type) \
do_nothing_ ## name(var_type *ptr) \
{ \
+ OPTIMIZER_HIDE_VAR(ptr); \
/* Will always be true, but compiler doesn't know. */ \
if ((unsigned long)ptr > 0x2) \
return DO_NOTHING_RETURN_ ## which(ptr); \
--
2.34.1
