1 files changed, 267 insertions, 0 deletions
diff --git a/tools/testing/selftests/mm/mlock-random-test.c b/tools/testing/selftests/mm/mlock-random-test.c
new file mode 100644
index 000000000000..1cd80b0f76c3
--- /dev/null
+++ b/tools/testing/selftests/mm/mlock-random-test.c
@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * It tests the mlock/mlock2() when they are invoked
+ * on randomly memory region.
+ */
+#include <unistd.h>
+#include <sys/resource.h>
+#include <sys/capability.h>
+#include <sys/mman.h>
+#include <linux/mman.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <time.h>
+#include "../kselftest.h"
+#include "mlock2.h"
+
+#define CHUNK_UNIT (128 * 1024)
+#define MLOCK_RLIMIT_SIZE (CHUNK_UNIT * 2)
+#define MLOCK_WITHIN_LIMIT_SIZE CHUNK_UNIT
+#define MLOCK_OUTOF_LIMIT_SIZE (CHUNK_UNIT * 3)
+
+#define TEST_LOOP 100
+#define PAGE_ALIGN(size, ps) (((size) + ((ps) - 1)) & ~((ps) - 1))
+
+int set_cap_limits(rlim_t max)
+{
+	struct rlimit new;
+	cap_t cap = cap_init();
+
+	new.rlim_cur = max;
+	new.rlim_max = max;
+	if (setrlimit(RLIMIT_MEMLOCK, &new)) {
+		ksft_perror("setrlimit() returns error\n");
+		return -1;
+	}
+
+	/* drop capabilities including CAP_IPC_LOCK */
+	if (cap_set_proc(cap)) {
+		ksft_perror("cap_set_proc() returns error\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+int get_proc_locked_vm_size(void)
+{
+	FILE *f;
+	int ret = -1;
+	char line[1024] = {0};
+	unsigned long lock_size = 0;
+
+	f = fopen("/proc/self/status", "r");
+	if (!f)
+		ksft_exit_fail_msg("fopen: %s\n", strerror(errno));
+
+	while (fgets(line, 1024, f)) {
+		if (strstr(line, "VmLck")) {
+			ret = sscanf(line, "VmLck:\t%8lu kB", &lock_size);
+			if (ret <= 0) {
+				fclose(f);
+				ksft_exit_fail_msg("sscanf() on VmLck error: %s: %d\n",
+						   line, ret);
+			}
+			fclose(f);
+			return (int)(lock_size << 10);
+		}
+	}
+
+	fclose(f);
+	ksft_exit_fail_msg("cannot parse VmLck in /proc/self/status: %s\n", strerror(errno));
+	return -1;
+}
+
+/*
+ * Get the MMUPageSize of the memory region including input
+ * address from proc file.
+ *
+ * return value: on error case, 0 will be returned.
+ * Otherwise the page size(in bytes) is returned.
+ */
+int get_proc_page_size(unsigned long addr)
+{
+	FILE *smaps;
+	char *line;
+	unsigned long mmupage_size = 0;
+	size_t size;
+
+	smaps = seek_to_smaps_entry(addr);
+	if (!smaps)
+		ksft_exit_fail_msg("Unable to parse /proc/self/smaps\n");
+
+	while (getline(&line, &size, smaps) > 0) {
+		if (!strstr(line, "MMUPageSize")) {
+			free(line);
+			line = NULL;
+			size = 0;
+			continue;
+		}
+
+		/* found the MMUPageSize of this section */
+		if (sscanf(line, "MMUPageSize:    %8lu kB", &mmupage_size) < 1)
+			ksft_exit_fail_msg("Unable to parse smaps entry for Size:%s\n",
+					   line);
+
+	}
+	free(line);
+	if (smaps)
+		fclose(smaps);
+	return mmupage_size << 10;
+}
+
+/*
+ * Test mlock/mlock2() on provided memory chunk.
+ * It expects the mlock/mlock2() to be successful (within rlimit)
+ *
+ * With allocated memory chunk [p, p + alloc_size), this
+ * test will choose start/len randomly to perform mlock/mlock2
+ * [start, start +  len] memory range. The range is within range
+ * of the allocated chunk.
+ *
+ * The memory region size alloc_size is within the rlimit.
+ * So we always expect a success of mlock/mlock2.
+ *
+ * VmLck is assumed to be 0 before this test.
+ *
+ *    return value: 0 - success
+ *    else: failure
+ */
+static void test_mlock_within_limit(char *p, int alloc_size)
+{
+	int i;
+	int ret = 0;
+	int locked_vm_size = 0;
+	struct rlimit cur;
+	int page_size = 0;
+
+	getrlimit(RLIMIT_MEMLOCK, &cur);
+	if (cur.rlim_cur < alloc_size)
+		ksft_exit_fail_msg("alloc_size[%d] < %u rlimit,lead to mlock failure\n",
+				   alloc_size, (unsigned int)cur.rlim_cur);
+
+	srand(time(NULL));
+	for (i = 0; i < TEST_LOOP; i++) {
+		/*
+		 * - choose mlock/mlock2 randomly
+		 * - choose lock_size randomly but lock_size < alloc_size
+		 * - choose start_offset randomly but p+start_offset+lock_size
+		 *   < p+alloc_size
+		 */
+		int is_mlock = !!(rand() % 2);
+		int lock_size = rand() % alloc_size;
+		int start_offset = rand() % (alloc_size - lock_size);
+
+		if (is_mlock)
+			ret = mlock(p + start_offset, lock_size);
+		else
+			ret = mlock2_(p + start_offset, lock_size,
+				       MLOCK_ONFAULT);
+
+		if (ret)
+			ksft_exit_fail_msg("%s() failure at |%p(%d)| mlock:|%p(%d)|\n",
+					   is_mlock ? "mlock" : "mlock2",
+					   p, alloc_size,
+					   p + start_offset, lock_size);
+	}
+
+	/*
+	 * Check VmLck left by the tests.
+	 */
+	locked_vm_size = get_proc_locked_vm_size();
+	page_size = get_proc_page_size((unsigned long)p);
+
+	if (locked_vm_size > PAGE_ALIGN(alloc_size, page_size) + page_size)
+		ksft_exit_fail_msg("%s left VmLck:%d on %d chunk\n",
+				   __func__, locked_vm_size, alloc_size);
+
+	ksft_test_result_pass("%s\n", __func__);
+}
+
+
+/*
+ * We expect the mlock/mlock2() to be fail (outof limitation)
+ *
+ * With allocated memory chunk [p, p + alloc_size), this
+ * test will randomly choose start/len and perform mlock/mlock2
+ * on [start, start+len] range.
+ *
+ * The memory region size alloc_size is above the rlimit.
+ * And the len to be locked is higher than rlimit.
+ * So we always expect a failure of mlock/mlock2.
+ * No locked page number should be increased as a side effect.
+ *
+ *    return value: 0 - success
+ *    else: failure
+ */
+static void test_mlock_outof_limit(char *p, int alloc_size)
+{
+	int i;
+	int ret = 0;
+	int locked_vm_size = 0, old_locked_vm_size = 0;
+	struct rlimit cur;
+
+	getrlimit(RLIMIT_MEMLOCK, &cur);
+	if (cur.rlim_cur >= alloc_size)
+		ksft_exit_fail_msg("alloc_size[%d] >%u rlimit, violates test condition\n",
+				   alloc_size, (unsigned int)cur.rlim_cur);
+
+	old_locked_vm_size = get_proc_locked_vm_size();
+	srand(time(NULL));
+	for (i = 0; i < TEST_LOOP; i++) {
+		int is_mlock = !!(rand() % 2);
+		int lock_size = (rand() % (alloc_size - cur.rlim_cur))
+			+ cur.rlim_cur;
+		int start_offset = rand() % (alloc_size - lock_size);
+
+		if (is_mlock)
+			ret = mlock(p + start_offset, lock_size);
+		else
+			ret = mlock2_(p + start_offset, lock_size,
+					MLOCK_ONFAULT);
+		if (ret == 0)
+			ksft_exit_fail_msg("%s() succeeds? on %p(%d) mlock%p(%d)\n",
+					   is_mlock ? "mlock" : "mlock2",
+					   p, alloc_size, p + start_offset, lock_size);
+	}
+
+	locked_vm_size = get_proc_locked_vm_size();
+	if (locked_vm_size != old_locked_vm_size)
+		ksft_exit_fail_msg("tests leads to new mlocked page: old[%d], new[%d]\n",
+				   old_locked_vm_size,
+				   locked_vm_size);
+
+	ksft_test_result_pass("%s\n", __func__);
+}
+
+int main(int argc, char **argv)
+{
+	char *p = NULL;
+
+	ksft_print_header();
+
+	if (set_cap_limits(MLOCK_RLIMIT_SIZE))
+		ksft_finished();
+
+	ksft_set_plan(2);
+
+	p = malloc(MLOCK_WITHIN_LIMIT_SIZE);
+	if (p == NULL)
+		ksft_exit_fail_msg("malloc() failure: %s\n", strerror(errno));
+
+	test_mlock_within_limit(p, MLOCK_WITHIN_LIMIT_SIZE);
+	munlock(p, MLOCK_WITHIN_LIMIT_SIZE);
+	free(p);
+
+	p = malloc(MLOCK_OUTOF_LIMIT_SIZE);
+	if (p == NULL)
+		ksft_exit_fail_msg("malloc() failure: %s\n", strerror(errno));
+
+	test_mlock_outof_limit(p, MLOCK_OUTOF_LIMIT_SIZE);
+	munlock(p, MLOCK_OUTOF_LIMIT_SIZE);
+	free(p);
+
+	ksft_finished();
+}