Re: [linux-next:master 14191/14955] vmlinux.o: error: objtool: amdgpu_vm_handle_fault+0x186: sibling call from callable instruction with modified stack frame

[Peter Zijlstra <peterz@infradead.org>]

On Wed, Jun 24, 2026 at 01:04:36PM +0200, Christian König wrote:

> > Best I can come up with is something like this. Not exactly nice, but
> > should be fairly trivial to do.
> 
> Yeah, definitely not nice. The macro was created exactly because
> people messed this approach up more than once.
> 
> I could live with some other hack/workaround, but clearly not with
> changing all users.
> 
> Maybe we can goto the fixed named label but have an extra variable to
> check that we are in the right scope or something like that.

The fixed name will break test_multiple_loops() and any other user that
actually does that (couldn't find one in a hurry).

That would look like so; by making the drm_exec_retry*() helpers depend
on __drm_exec_loop, it can only be used inside
drm_exec_until_all_locked().



---
diff --git a/drivers/gpu/drm/tests/drm_exec_test.c b/drivers/gpu/drm/tests/drm_exec_test.c
index 2fc47f3b463b..fbb887930e6d 100644
--- a/drivers/gpu/drm/tests/drm_exec_test.c
+++ b/drivers/gpu/drm/tests/drm_exec_test.c
@@ -166,9 +166,9 @@ static void test_prepare_array(struct kunit *test)
 	drm_gem_private_object_init(priv->drm, gobj2, PAGE_SIZE);
 
 	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
-	drm_exec_until_all_locked(&exec)
-		ret = drm_exec_prepare_array(&exec, array, ARRAY_SIZE(array),
-					     1);
+	drm_exec_until_all_locked(&exec) {
+		ret = drm_exec_prepare_array(&exec, array, ARRAY_SIZE(array), 1);
+	}
 	KUNIT_EXPECT_EQ(test, ret, 0);
 	drm_exec_fini(&exec);
 
@@ -176,26 +176,6 @@ static void test_prepare_array(struct kunit *test)
 	drm_gem_private_object_fini(gobj2);
 }
 
-static void test_multiple_loops(struct kunit *test)
-{
-	struct drm_exec exec;
-
-	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
-	drm_exec_until_all_locked(&exec)
-	{
-		break;
-	}
-	drm_exec_fini(&exec);
-
-	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
-	drm_exec_until_all_locked(&exec)
-	{
-		break;
-	}
-	drm_exec_fini(&exec);
-	KUNIT_SUCCEED(test);
-}
-
 static struct kunit_case drm_exec_tests[] = {
 	KUNIT_CASE(sanitycheck),
 	KUNIT_CASE(test_lock),
@@ -203,7 +183,6 @@ static struct kunit_case drm_exec_tests[] = {
 	KUNIT_CASE(test_duplicates),
 	KUNIT_CASE(test_prepare),
 	KUNIT_CASE(test_prepare_array),
-	KUNIT_CASE(test_multiple_loops),
 	{}
 };
 
diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h
index 8725ba92ff91..4a6b6aba4f15 100644
--- a/include/drm/drm_exec.h
+++ b/include/drm/drm_exec.h
@@ -101,17 +101,6 @@ drm_exec_obj(struct drm_exec *exec, unsigned long index)
 #define drm_exec_for_each_locked_object_reverse(exec, obj)		\
 	__drm_exec_for_each_locked_object_reverse(exec, obj, __UNIQUE_ID(drm_exec))
 
-/*
- * Helper to drm_exec_until_all_locked(). Don't use directly.
- *
- * Since labels can't be defined local to the loop's body we use a jump pointer
- * to make sure that the retry is only used from within the loop's body.
- */
-#define __drm_exec_until_all_locked(exec, _label)			 \
-_label:									 \
-	for (void *const __maybe_unused __drm_exec_retry_ptr = &&_label; \
-	     drm_exec_cleanup(exec);)
-
 /**
  * drm_exec_until_all_locked - loop until all GEM objects are locked
  * @exec: drm_exec object
@@ -121,7 +110,8 @@ _label:									 \
  * guaranteed that no GEM object is locked.
  */
 #define drm_exec_until_all_locked(exec)					\
-	__drm_exec_until_all_locked(exec, __UNIQUE_ID(drm_exec))
+	__drm_exec_retry: __maybe_unused;				\
+	for (bool __drm_exec_loop __maybe_unused = true; drm_exec_cleanup(exec);)
 
 /**
  * drm_exec_retry_on_contention - restart the loop to grap all locks
@@ -132,8 +122,9 @@ _label:									 \
  */
 #define drm_exec_retry_on_contention(exec)			\
 	do {							\
-		if (unlikely(drm_exec_is_contended(exec)))	\
-			goto *__drm_exec_retry_ptr;		\
+		if (unlikely(__drm_exec_loop &&			\
+			     drm_exec_is_contended(exec)))	\
+			goto __drm_exec_retry;			\
 	} while (0)
 
 /**
@@ -157,8 +148,9 @@ static inline bool drm_exec_is_contended(struct drm_exec *exec)
  */
 #define drm_exec_retry(_exec)					\
 	do {							\
-		WARN_ON((_exec)->contended != DRM_EXEC_DUMMY);	\
-		goto *__drm_exec_retry_ptr;			\
+		WARN_ON(__drm_exec_loop &&			\
+			(_exec)->contended != DRM_EXEC_DUMMY);	\
+		goto __drm_exec_retry;				\
 	} while (0)
 
 /**