selftests: expanding more mlock selftest

This patch will randomly perform mlock/mlock2 on a given memory region,
and verify the RLIMIT_MEMLOCK limitation works properly.

Suggested-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/1473325970-11393-4-git-send-email-wei.guo.simon@gmail.com
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Eric B Munson <emunson@akamai.com>
Cc: Simon Guo <wei.guo.simon@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Alexey Klimov <klimov.linux@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 295 insertions, 78 deletions

diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
index a0412a80b679..bbab7f4664ac 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -10,7 +10,7 @@ BINARIES += on-fault-limit
 BINARIES += thuge-gen
 BINARIES += transhuge-stress
 BINARIES += userfaultfd
-BINARIES += mlock-intersect-test
+BINARIES += mlock-random-test
 
 all: $(BINARIES)
 %: %.c
@@ -18,7 +18,7 @@ all: $(BINARIES)
 userfaultfd: userfaultfd.c ../../../../usr/include/linux/kernel.h
         $(CC) $(CFLAGS) -O2 -o $@ $< -lpthread
 
-mlock-intersect-test: mlock-intersect-test.c
+mlock-random-test: mlock-random-test.c
         $(CC) $(CFLAGS) -o $@ $< -lcap
 
 ../../../../usr/include/linux/kernel.h:
diff --git a/tools/testing/selftests/vm/mlock-intersect-test.c b/tools/testing/selftests/vm/mlock-intersect-test.c
deleted file mode 100644
index f78e68a0967c..000000000000
--- a/tools/testing/selftests/vm/mlock-intersect-test.c
+++ /dev/null
@@ -1,76 +0,0 @@
-/*
- * It tests the duplicate mlock result:
- * - the ulimit of lock page is 64k
- * - allocate address area 64k starting from p
- * - mlock   [p -- p + 30k]
- * - Then mlock address  [ p -- p + 40k ]
- *
- * It should succeed since totally we locked
- * 40k < 64k limitation.
- *
- * It should not be run with CAP_IPC_LOCK.
- */
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <sys/resource.h>
-#include <sys/capability.h>
-#include <sys/mman.h>
-#include "mlock2.h"
-
-int main(int argc, char **argv)
-{
-        struct rlimit new;
-        char *p = NULL;
-        cap_t cap = cap_init();
-        int i;
-
-        /* drop capabilities including CAP_IPC_LOCK */
-        if (cap_set_proc(cap))
-                return -1;
-
-        /* set mlock limits to 64k */
-        new.rlim_cur = 65536;
-        new.rlim_max = 65536;
-        setrlimit(RLIMIT_MEMLOCK, &new);
-
-        /* test VM_LOCK */
-        p = malloc(1024 * 64);
-        if (mlock(p, 1024 * 30)) {
-                printf("mlock() 30k return failure.\n");
-                return -1;
-        }
-        for (i = 0; i < 10; i++) {
-                if (mlock(p, 1024 * 40)) {
-                        printf("mlock() #%d 40k returns failure.\n", i);
-                        return -1;
-                }
-        }
-        for (i = 0; i < 10; i++) {
-                if (mlock2_(p, 1024 * 40, MLOCK_ONFAULT)) {
-                        printf("mlock2_() #%d 40k returns failure.\n", i);
-                        return -1;
-                }
-        }
-        free(p);
-
-        /* Test VM_LOCKONFAULT */
-        p = malloc(1024 * 64);
-        if (mlock2_(p, 1024 * 30, MLOCK_ONFAULT)) {
-                printf("mlock2_() 30k return failure.\n");
-                return -1;
-        }
-        for (i = 0; i < 10; i++) {
-                if (mlock2_(p, 1024 * 40, MLOCK_ONFAULT)) {
-                        printf("mlock2_() #%d 40k returns failure.\n", i);
-                        return -1;
-                }
-        }
-        for (i = 0; i < 10; i++) {
-                if (mlock(p, 1024 * 40)) {
-                        printf("mlock() #%d 40k returns failure.\n", i);
-                        return -1;
-                }
-        }
-        return 0;
-}
diff --git a/tools/testing/selftests/vm/mlock-random-test.c b/tools/testing/selftests/vm/mlock-random-test.c
new file mode 100644
index 000000000000..83de4f58d262
--- /dev/null
+++ b/tools/testing/selftests/vm/mlock-random-test.c
@@ -0,0 +1,293 @@
+/*
+ * 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 <fcntl.h>
+#include <string.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <time.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)) {
+                perror("setrlimit() returns error\n");
+                return -1;
+        }
+
+        /* drop capabilities including CAP_IPC_LOCK */
+        if (cap_set_proc(cap)) {
+                perror("cap_set_proc() returns error\n");
+                return -2;
+        }
+
+        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) {
+                perror("fopen");
+                return -1;
+        }
+
+        while (fgets(line, 1024, f)) {
+                if (strstr(line, "VmLck")) {
+                        ret = sscanf(line, "VmLck:\t%8lu kB", &lock_size);
+                        if (ret <= 0) {
+                                printf("sscanf() on VmLck error: %s: %d\n",
+                                                line, ret);
+                                fclose(f);
+                                return -1;
+                        }
+                        fclose(f);
+                        return (int)(lock_size << 10);
+                }
+        }
+
+        perror("cann't parse VmLck in /proc/self/status\n");
+        fclose(f);
+        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) {
+                printf("Unable to parse /proc/self/smaps\n");
+                return 0;
+        }
+
+        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) {
+                        printf("Unable to parse smaps entry for Size:%s\n",
+                                        line);
+                        break;
+                }
+
+        }
+        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
+ */
+int 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) {
+                printf("alloc_size[%d] < %u rlimit,lead to mlock failure\n",
+                                alloc_size, (unsigned int)cur.rlim_cur);
+                return -1;
+        }
+
+        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) {
+                        printf("%s() failure at |%p(%d)| mlock:|%p(%d)|\n",
+                                        is_mlock ? "mlock" : "mlock2",
+                                        p, alloc_size,
+                                        p + start_offset, lock_size);
+                        return ret;
+                }
+        }
+
+        /*
+         * Check VmLck left by the tests.
+         */
+        locked_vm_size = get_proc_locked_vm_size();
+        page_size = get_proc_page_size((unsigned long)p);
+        if (page_size == 0) {
+                printf("cannot get proc MMUPageSize\n");
+                return -1;
+        }
+
+        if (locked_vm_size > PAGE_ALIGN(alloc_size, page_size) + page_size) {
+                printf("test_mlock_within_limit() left VmLck:%d on %d chunk\n",
+                                locked_vm_size, alloc_size);
+                return -1;
+        }
+
+        return 0;
+}
+
+
+/*
+ * 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
+ */
+int 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) {
+                printf("alloc_size[%d] >%u rlimit, violates test condition\n",
+                                alloc_size, (unsigned int)cur.rlim_cur);
+                return -1;
+        }
+
+        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) {
+                        printf("%s() succeeds? on %p(%d) mlock%p(%d)\n",
+                                        is_mlock ? "mlock" : "mlock2",
+                                        p, alloc_size,
+                                        p + start_offset, lock_size);
+                        return -1;
+                }
+        }
+
+        locked_vm_size = get_proc_locked_vm_size();
+        if (locked_vm_size != old_locked_vm_size) {
+                printf("tests leads to new mlocked page: old[%d], new[%d]\n",
+                                old_locked_vm_size,
+                                locked_vm_size);
+                return -1;
+        }
+
+        return 0;
+}
+
+int main(int argc, char **argv)
+{
+        char *p = NULL;
+        int ret = 0;
+
+        if (set_cap_limits(MLOCK_RLIMIT_SIZE))
+                return -1;
+
+        p = malloc(MLOCK_WITHIN_LIMIT_SIZE);
+        if (p == NULL) {
+                perror("malloc() failure\n");
+                return -1;
+        }
+        ret = test_mlock_within_limit(p, MLOCK_WITHIN_LIMIT_SIZE);
+        if (ret)
+                return ret;
+        munlock(p, MLOCK_WITHIN_LIMIT_SIZE);
+        free(p);
+
+
+        p = malloc(MLOCK_OUTOF_LIMIT_SIZE);
+        if (p == NULL) {
+                perror("malloc() failure\n");
+                return -1;
+        }
+        ret = test_mlock_outof_limit(p, MLOCK_OUTOF_LIMIT_SIZE);
+        if (ret)
+                return ret;
+        munlock(p, MLOCK_OUTOF_LIMIT_SIZE);
+        free(p);
+
+        return 0;
+}