clang fails to see that rbd_assert(0) ends in an unreachable code
path and warns about a subsequent use of an uninitialized variable
when CONFIG_PROFILE_ANNOTATED_BRANCHES is set:
drivers/block/rbd.c:2402:4: error: variable 'ret' is used uninitialized whenever 'if' condition is false
[-Werror,-Wsometimes-uninitialized]
rbd_assert(0);
^~~~~~~~~~~~~
drivers/block/rbd.c:563:7: note: expanded from macro 'rbd_assert'
if (unlikely(!(expr))) { \
^~~~~~~~~~~~~~~~~
include/linux/compiler.h:48:23: note: expanded from macro 'unlikely'
# define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/block/rbd.c:2410:6: note: uninitialized use occurs here
if (ret) {
^~~
drivers/block/rbd.c:2402:4: note: remove the 'if' if its condition is always true
rbd_assert(0);
^
drivers/block/rbd.c:563:3: note: expanded from macro 'rbd_assert'
if (unlikely(!(expr))) { \
^
drivers/block/rbd.c:2376:9: note: initialize the variable 'ret' to silence this warning
int ret;
^
= 0
1 error generated.
This seems to be a bug in clang, but is easy to work around by using
an unconditional BUG().
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/block/rbd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 4ba967d65cf9..cbcc3baf3807 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2399,7 +2399,7 @@ static int rbd_obj_read_from_parent(struct rbd_obj_request *obj_req)
&obj_req->bvec_pos);
break;
default:
- rbd_assert(0);
+ BUG();
}
} else {
ret = rbd_img_fill_from_bvecs(child_img_req,
--
2.20.0
