test/file-exit-unreg: check defer tw file exit unregistration

With the resource node rewrite for kernel 6.13, the punt of defer
tw at fail time over the normal task_work can trigger a lockdep
complaint. Check that this proceeds without warnings.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

test/Makefile

@@ -95,6 +95,7 @@ test_srcs := \
 	fd-pass.c \
 	fdinfo.c \
 	fifo-nonblock-read.c \
+	file-exit-unreg.c \
 	file-register.c \
 	files-exit-hang-poll.c \
 	files-exit-hang-timeout.c \

test/file-exit-unreg.c

@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test that a defer task_work file with tags unregistration
+ *		doesn't trigger a lockdep violation
+ *
+ */
+#include <stdio.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "liburing.h"
+#include "helpers.h"
+
+int main(int argc, char *argv[])
+{
+	__u64 tags[2] = { 1, 2 };
+	struct io_uring ring;
+	int fds[2], ret;
+
+	if (argc > 1)
+		return T_EXIT_SKIP;
+
+	if (pipe(fds) < 0) {
+		perror("pipe");
+		return 1;
+	}
+
+	ret = io_uring_queue_init(4, &ring, IORING_SETUP_SINGLE_ISSUER|IORING_SETUP_DEFER_TASKRUN);
+	if (ret == -EINVAL) {
+		return T_EXIT_SKIP;
+	} else if (ret < 0) {
+		fprintf(stderr, "queue_init: %d\n", ret);
+		return T_EXIT_FAIL;
+	}
+
+	ret = io_uring_register_files_tags(&ring, fds, tags, 2);
+	if (ret == -EINVAL) {
+		return T_EXIT_SKIP;
+	} else {
+		fprintf(stderr, "file_register_init: %d\n", ret);
+		return T_EXIT_FAIL;
+	}
+
+	io_uring_queue_exit(&ring);
+	sleep(1);
+	return 0;
+}