Re: [PATCH v5 13/17] rv: Add KUnit mock for current

Il 29 luglio 2026 18:17:31 UTC, Wen Yang [off-list ref] ha scritto:

quoted

+#define rv_get_current() (unlikely(kunit_get_current_test()) ? rv_get_mock_current() : current)

 
...

quoted

+/*
+ * rv_get_mock_current() is called only if we are running from a KUnit test.
+ * This can occur from a legitimate RV test or any unrelated test running when
+ * a real RV monitor is active and triggering events.
+ * We assume the former case is the only one where mock_current is not NULL and
+ * can occur only sequentially (KUnit doesn't run tests in parallel).
+ * We cannot rely on the test's context because there is no way to safely
+ * understand from which test we are running and KUnit utilities require
+ * locking, which is unsafe from NMI or scheduling context.
+ * Note that it is not possible for a real RV monitor to run when the RV KUnit
+ * tests are running (see rv_set_testing()).
+ */
+static struct task_struct *mock_current;
+
+void rv_mock_current(struct task_struct *tsk)
+{
+	mock_current = tsk;
+}
+EXPORT_SYMBOL_IF_KUNIT(rv_mock_current);
+
+struct task_struct *rv_get_mock_current(void)
+{
+	return mock_current ?: current;
+}
+EXPORT_SYMBOL_GPL(rv_get_mock_current);
  #endif

rv_mock_current() uses EXPORT_SYMBOL_IF_KUNIT, but rv_get_mock_current() uses EXPORT_SYMBOL_GPL. Both are defined inside the same CONFIG_RV_MONITORS_KUNIT_TEST block, so rv_get_mock_current should use EXPORT_SYMBOL_IF_KUNIT as well, otherwise it leaks a test-only symbol into production builds.

With that fixed:
Reviewed-by: Wen Yang <redacted>

Thanks for the review.
This was intentional however: rv_get_current() can be called by any monitor, those don't have to be KUnit.
Since rv_get_current() is a macro also calling rv_get_mock_current() we need to be able to link that too.

The idea is that a "real" (non-kunit) monitor handler could be run when interrupting a KUnit test (not an RV one, we make sure of that). In that case we do call rv_get_mock_current() and return current after the function call.

rv_mock_current() CANNOT be called outside of the RV KUnit test cases, it uses a global variable (for problems I tried to explain in the comment), so should be exported only to KUnit and called directly from the test case.

Does it make sense to you?

Thanks,
Gabriele