1 files changed, 109 insertions, 0 deletions
diff --git a/tools/testing/selftests/mm/hugetlb_fault_after_madv.c b/tools/testing/selftests/mm/hugetlb_fault_after_madv.c
new file mode 100644
index 000000000000..e2640529dbb2
--- /dev/null
+++ b/tools/testing/selftests/mm/hugetlb_fault_after_madv.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <setjmp.h>
+#include <signal.h>
+
+#include "vm_util.h"
+#include "../kselftest.h"
+
+#define INLOOP_ITER 100
+
+static char *huge_ptr;
+static size_t huge_page_size;
+
+static sigjmp_buf sigbuf;
+static bool sigbus_triggered;
+
+static void signal_handler(int signal)
+{
+	if (signal == SIGBUS) {
+		sigbus_triggered = true;
+		siglongjmp(sigbuf, 1);
+	}
+}
+
+/* Touch the memory while it is being madvised() */
+void *touch(void *unused)
+{
+	char *ptr = (char *)huge_ptr;
+
+	if (sigsetjmp(sigbuf, 1))
+		return NULL;
+
+	for (int i = 0; i < INLOOP_ITER; i++)
+		ptr[0] = '.';
+
+	return NULL;
+}
+
+void *madv(void *unused)
+{
+	usleep(rand() % 10);
+
+	for (int i = 0; i < INLOOP_ITER; i++)
+		madvise(huge_ptr, huge_page_size, MADV_DONTNEED);
+
+	return NULL;
+}
+
+int main(void)
+{
+	unsigned long free_hugepages;
+	pthread_t thread1, thread2;
+	/*
+	 * On kernel 6.4, we are able to reproduce the problem with ~1000
+	 * interactions
+	 */
+	int max = 10000;
+	int err;
+
+	ksft_print_header();
+	ksft_set_plan(1);
+
+	srand(getpid());
+
+	if (signal(SIGBUS, signal_handler) == SIG_ERR)
+		ksft_exit_skip("Could not register signal handler.");
+
+	huge_page_size = default_huge_page_size();
+	if (!huge_page_size)
+		ksft_exit_skip("Could not detect default hugetlb page size.");
+
+	ksft_print_msg("[INFO] detected default hugetlb page size: %zu KiB\n",
+		       huge_page_size / 1024);
+
+	free_hugepages = get_free_hugepages();
+	if (free_hugepages != 1) {
+		ksft_exit_skip("This test needs one and only one page to execute. Got %lu\n",
+			       free_hugepages);
+	}
+
+	while (max--) {
+		huge_ptr = mmap(NULL, huge_page_size, PROT_READ | PROT_WRITE,
+				MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB,
+				-1, 0);
+
+		if ((unsigned long)huge_ptr == -1)
+			ksft_exit_skip("Failed to allocated huge page\n");
+
+		pthread_create(&thread1, NULL, madv, NULL);
+		pthread_create(&thread2, NULL, touch, NULL);
+
+		pthread_join(thread1, NULL);
+		pthread_join(thread2, NULL);
+		munmap(huge_ptr, huge_page_size);
+	}
+
+	ksft_test_result(!sigbus_triggered, "SIGBUS behavior\n");
+
+	err = ksft_get_fail_cnt();
+	if (err)
+		ksft_exit_fail_msg("%d out of %d tests failed\n",
+				   err, ksft_test_num());
+	ksft_exit_pass();
+}