Merge tag 'linux_kselftest-kunit-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull kunit updates from Shuah Khan:

 - fix race condition in try-catch completion

 - change __kunit_test_suites_init() to exit early if there is
   nothing to test

 - change string-stream-test to use KUNIT_DEFINE_ACTION_WRAPPER

 - move fault tests behind KUNIT_FAULT_TEST Kconfig option

 - kthread test fixes and improvements

 - iov_iter test fixes

* tag 'linux_kselftest-kunit-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  kunit: bail out early in __kunit_test_suites_init() if there are no suites to test
  kunit: string-stream-test: use KUNIT_DEFINE_ACTION_WRAPPER
  kunit: test: Move fault tests behind KUNIT_FAULT_TEST Kconfig option
  kunit: unregister the device on error
  kunit: Fix race condition in try-catch completion
  kunit: Add tests for fault
  kunit: Print last test location on fault
  kunit: Fix KUNIT_SUCCESS() calls in iov_iter tests
  kunit: Handle test faults
  kunit: Fix timeout message
  kunit: Fix kthread reference
  kunit: Handle thread creation error

1 files changed, 29 insertions, 11 deletions

diff --git a/lib/kunit/try-catch.c b/lib/kunit/try-catch.c
index f7825991d576..6bbe0025b079 100644
--- a/lib/kunit/try-catch.c
+++ b/lib/kunit/try-catch.c
@@ -11,13 +11,14 @@
 #include <linux/completion.h>
 #include <linux/kernel.h>
 #include <linux/kthread.h>
+#include <linux/sched/task.h>
 
 #include "try-catch-impl.h"
 
 void __noreturn kunit_try_catch_throw(struct kunit_try_catch *try_catch)
 {
 	try_catch->try_result = -EFAULT;
-	kthread_complete_and_exit(try_catch->try_completion, -EFAULT);
+	kthread_exit(0);
 }
 EXPORT_SYMBOL_GPL(kunit_try_catch_throw);
 
@@ -25,9 +26,12 @@ static int kunit_generic_run_threadfn_adapter(void *data)
 {
 	struct kunit_try_catch *try_catch = data;
 
+	try_catch->try_result = -EINTR;
 	try_catch->try(try_catch->context);
+	if (try_catch->try_result == -EINTR)
+		try_catch->try_result = 0;
 
-	kthread_complete_and_exit(try_catch->try_completion, 0);
+	return 0;
 }
 
 static unsigned long kunit_test_timeout(void)
@@ -57,30 +61,38 @@ static unsigned long kunit_test_timeout(void)
 
 void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
 {
-	DECLARE_COMPLETION_ONSTACK(try_completion);
 	struct kunit *test = try_catch->test;
 	struct task_struct *task_struct;
+	struct completion *task_done;
 	int exit_code, time_remaining;
 
 	try_catch->context = context;
-	try_catch->try_completion = &try_completion;
 	try_catch->try_result = 0;
-	task_struct = kthread_run(kunit_generic_run_threadfn_adapter,
-				  try_catch,
-				  "kunit_try_catch_thread");
+	task_struct = kthread_create(kunit_generic_run_threadfn_adapter,
+				     try_catch, "kunit_try_catch_thread");
 	if (IS_ERR(task_struct)) {
+		try_catch->try_result = PTR_ERR(task_struct);
 		try_catch->catch(try_catch->context);
 		return;
 	}
+	get_task_struct(task_struct);
+	/*
+	 * As for a vfork(2), task_struct->vfork_done (pointing to the
+	 * underlying kthread->exited) can be used to wait for the end of a
+	 * kernel thread. It is set to NULL when the thread exits, so we
+	 * keep a copy here.
+	 */
+	task_done = task_struct->vfork_done;
+	wake_up_process(task_struct);
 
-	time_remaining = wait_for_completion_timeout(&try_completion,
+	time_remaining = wait_for_completion_timeout(task_done,
 						     kunit_test_timeout());
 	if (time_remaining == 0) {
-		kunit_err(test, "try timed out\n");
 		try_catch->try_result = -ETIMEDOUT;
 		kthread_stop(task_struct);
 	}
 
+	put_task_struct(task_struct);
 	exit_code = try_catch->try_result;
 
 	if (!exit_code)
@@ -88,8 +100,14 @@ void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
 
 	if (exit_code == -EFAULT)
 		try_catch->try_result = 0;
-	else if (exit_code == -EINTR)
-		kunit_err(test, "wake_up_process() was never called\n");
+	else if (exit_code == -EINTR) {
+		if (test->last_seen.file)
+			kunit_err(test, "try faulted: last line seen %s:%d\n",
+				  test->last_seen.file, test->last_seen.line);
+		else
+			kunit_err(test, "try faulted\n");
+	} else if (exit_code == -ETIMEDOUT)
+		kunit_err(test, "try timed out\n");
 	else if (exit_code)
 		kunit_err(test, "Unknown error: %d\n", exit_code);