1 files changed, 267 insertions, 12 deletions

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 1eae79ae5b4e..a2c53a3d223d 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -66,6 +66,8 @@
 #include <sys/wait.h>
 #include <pthread.h>
 #include <linux/userfaultfd.h>
+#include <setjmp.h>
+#include <stdbool.h>
 
 #ifdef __NR_userfaultfd
 
@@ -82,11 +84,17 @@ static int bounces;
 #define TEST_SHMEM	3
 static int test_type;
 
+/* exercise the test_uffdio_*_eexist every ALARM_INTERVAL_SECS */
+#define ALARM_INTERVAL_SECS 10
+static volatile bool test_uffdio_copy_eexist = true;
+static volatile bool test_uffdio_zeropage_eexist = true;
+
+static bool map_shared;
 static int huge_fd;
 static char *huge_fd_off0;
 static unsigned long long *count_verify;
 static int uffd, uffd_flags, finished, *pipefd;
-static char *area_src, *area_dst;
+static char *area_src, *area_src_alias, *area_dst, *area_dst_alias;
 static char *zeropage;
 pthread_attr_t attr;
 
@@ -125,6 +133,9 @@ static void anon_allocate_area(void **alloc_area)
 	}
 }
 
+static void noop_alias_mapping(__u64 *start, size_t len, unsigned long offset)
+{
+}
 
 /* HugeTLB memory */
 static int hugetlb_release_pages(char *rel_area)
@@ -145,17 +156,51 @@ static int hugetlb_release_pages(char *rel_area)
 
 static void hugetlb_allocate_area(void **alloc_area)
 {
+	void *area_alias = NULL;
+	char **alloc_area_alias;
 	*alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
-				MAP_PRIVATE | MAP_HUGETLB, huge_fd,
-				*alloc_area == area_src ? 0 :
-				nr_pages * page_size);
+			   (map_shared ? MAP_SHARED : MAP_PRIVATE) |
+			   MAP_HUGETLB,
+			   huge_fd, *alloc_area == area_src ? 0 :
+			   nr_pages * page_size);
 	if (*alloc_area == MAP_FAILED) {
 		fprintf(stderr, "mmap of hugetlbfs file failed\n");
 		*alloc_area = NULL;
 	}
 
-	if (*alloc_area == area_src)
+	if (map_shared) {
+		area_alias = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
+				  MAP_SHARED | MAP_HUGETLB,
+				  huge_fd, *alloc_area == area_src ? 0 :
+				  nr_pages * page_size);
+		if (area_alias == MAP_FAILED) {
+			if (munmap(*alloc_area, nr_pages * page_size) < 0)
+				perror("hugetlb munmap"), exit(1);
+			*alloc_area = NULL;
+			return;
+		}
+	}
+	if (*alloc_area == area_src) {
 		huge_fd_off0 = *alloc_area;
+		alloc_area_alias = &area_src_alias;
+	} else {
+		alloc_area_alias = &area_dst_alias;
+	}
+	if (area_alias)
+		*alloc_area_alias = area_alias;
+}
+
+static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset)
+{
+	if (!map_shared)
+		return;
+	/*
+	 * We can't zap just the pagetable with hugetlbfs because
+	 * MADV_DONTEED won't work. So exercise -EEXIST on a alias
+	 * mapping where the pagetables are not established initially,
+	 * this way we'll exercise the -EEXEC at the fs level.
+	 */
+	*start = (unsigned long) area_dst_alias + offset;
 }
 
 /* Shared memory */
@@ -185,6 +230,7 @@ struct uffd_test_ops {
 	unsigned long expected_ioctls;
 	void (*allocate_area)(void **alloc_area);
 	int (*release_pages)(char *rel_area);
+	void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset);
 };
 
 #define ANON_EXPECTED_IOCTLS		((1 << _UFFDIO_WAKE) | \
@@ -195,18 +241,21 @@ static struct uffd_test_ops anon_uffd_test_ops = {
 	.expected_ioctls = ANON_EXPECTED_IOCTLS,
 	.allocate_area	= anon_allocate_area,
 	.release_pages	= anon_release_pages,
+	.alias_mapping = noop_alias_mapping,
 };
 
 static struct uffd_test_ops shmem_uffd_test_ops = {
-	.expected_ioctls = UFFD_API_RANGE_IOCTLS_BASIC,
+	.expected_ioctls = ANON_EXPECTED_IOCTLS,
 	.allocate_area	= shmem_allocate_area,
 	.release_pages	= shmem_release_pages,
+	.alias_mapping = noop_alias_mapping,
 };
 
 static struct uffd_test_ops hugetlb_uffd_test_ops = {
 	.expected_ioctls = UFFD_API_RANGE_IOCTLS_BASIC,
 	.allocate_area	= hugetlb_allocate_area,
 	.release_pages	= hugetlb_release_pages,
+	.alias_mapping = hugetlb_alias_mapping,
 };
 
 static struct uffd_test_ops *uffd_test_ops;
@@ -331,6 +380,23 @@ static void *locking_thread(void *arg)
 	return NULL;
 }
 
+static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy,
+			    unsigned long offset)
+{
+	uffd_test_ops->alias_mapping(&uffdio_copy->dst,
+				     uffdio_copy->len,
+				     offset);
+	if (ioctl(ufd, UFFDIO_COPY, uffdio_copy)) {
+		/* real retval in ufdio_copy.copy */
+		if (uffdio_copy->copy != -EEXIST)
+			fprintf(stderr, "UFFDIO_COPY retry error %Ld\n",
+				uffdio_copy->copy), exit(1);
+	} else {
+		fprintf(stderr,	"UFFDIO_COPY retry unexpected %Ld\n",
+			uffdio_copy->copy), exit(1);
+	}
+}
+
 static int copy_page(int ufd, unsigned long offset)
 {
 	struct uffdio_copy uffdio_copy;
@@ -351,8 +417,13 @@ static int copy_page(int ufd, unsigned long offset)
 	} else if (uffdio_copy.copy != page_size) {
 		fprintf(stderr, "UFFDIO_COPY unexpected copy %Ld\n",
 			uffdio_copy.copy), exit(1);
-	} else
+	} else {
+		if (test_uffdio_copy_eexist) {
+			test_uffdio_copy_eexist = false;
+			retry_copy_page(ufd, &uffdio_copy, offset);
+		}
 		return 1;
+	}
 	return 0;
 }
 
@@ -408,6 +479,7 @@ static void *uffd_poll_thread(void *arg)
 				userfaults++;
 			break;
 		case UFFD_EVENT_FORK:
+			close(uffd);
 			uffd = msg.arg.fork.ufd;
 			pollfd[0].fd = uffd;
 			break;
@@ -572,6 +644,17 @@ static int userfaultfd_open(int features)
 	return 0;
 }
 
+sigjmp_buf jbuf, *sigbuf;
+
+static void sighndl(int sig, siginfo_t *siginfo, void *ptr)
+{
+	if (sig == SIGBUS) {
+		if (sigbuf)
+			siglongjmp(*sigbuf, 1);
+		abort();
+	}
+}
+
 /*
  * For non-cooperative userfaultfd test we fork() a process that will
  * generate pagefaults, will mremap the area monitored by the
@@ -585,19 +668,59 @@ static int userfaultfd_open(int features)
  * The release of the pages currently generates event for shmem and
  * anonymous memory (UFFD_EVENT_REMOVE), hence it is not checked
  * for hugetlb.
+ * For signal test(UFFD_FEATURE_SIGBUS), signal_test = 1, we register
+ * monitored area, generate pagefaults and test that signal is delivered.
+ * Use UFFDIO_COPY to allocate missing page and retry. For signal_test = 2
+ * test robustness use case - we release monitored area, fork a process
+ * that will generate pagefaults and verify signal is generated.
+ * This also tests UFFD_FEATURE_EVENT_FORK event along with the signal
+ * feature. Using monitor thread, verify no userfault events are generated.
  */
-static int faulting_process(void)
+static int faulting_process(int signal_test)
 {
 	unsigned long nr;
 	unsigned long long count;
 	unsigned long split_nr_pages;
+	unsigned long lastnr;
+	struct sigaction act;
+	unsigned long signalled = 0;
 
 	if (test_type != TEST_HUGETLB)
 		split_nr_pages = (nr_pages + 1) / 2;
 	else
 		split_nr_pages = nr_pages;
 
+	if (signal_test) {
+		sigbuf = &jbuf;
+		memset(&act, 0, sizeof(act));
+		act.sa_sigaction = sighndl;
+		act.sa_flags = SA_SIGINFO;
+		if (sigaction(SIGBUS, &act, 0)) {
+			perror("sigaction");
+			return 1;
+		}
+		lastnr = (unsigned long)-1;
+	}
+
 	for (nr = 0; nr < split_nr_pages; nr++) {
+		if (signal_test) {
+			if (sigsetjmp(*sigbuf, 1) != 0) {
+				if (nr == lastnr) {
+					fprintf(stderr, "Signal repeated\n");
+					return 1;
+				}
+
+				lastnr = nr;
+				if (signal_test == 1) {
+					if (copy_page(uffd, nr * page_size))
+						signalled++;
+				} else {
+					signalled++;
+					continue;
+				}
+			}
+		}
+
 		count = *area_count(area_dst, nr);
 		if (count != count_verify[nr]) {
 			fprintf(stderr,
@@ -607,6 +730,9 @@ static int faulting_process(void)
 		}
 	}
 
+	if (signal_test)
+		return signalled != split_nr_pages;
+
 	if (test_type == TEST_HUGETLB)
 		return 0;
 
@@ -636,6 +762,23 @@ static int faulting_process(void)
 	return 0;
 }
 
+static void retry_uffdio_zeropage(int ufd,
+				  struct uffdio_zeropage *uffdio_zeropage,
+				  unsigned long offset)
+{
+	uffd_test_ops->alias_mapping(&uffdio_zeropage->range.start,
+				     uffdio_zeropage->range.len,
+				     offset);
+	if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
+		if (uffdio_zeropage->zeropage != -EEXIST)
+			fprintf(stderr, "UFFDIO_ZEROPAGE retry error %Ld\n",
+				uffdio_zeropage->zeropage), exit(1);
+	} else {
+		fprintf(stderr, "UFFDIO_ZEROPAGE retry unexpected %Ld\n",
+			uffdio_zeropage->zeropage), exit(1);
+	}
+}
+
 static int uffdio_zeropage(int ufd, unsigned long offset)
 {
 	struct uffdio_zeropage uffdio_zeropage;
@@ -670,8 +813,14 @@ static int uffdio_zeropage(int ufd, unsigned long offset)
 		if (uffdio_zeropage.zeropage != page_size) {
 			fprintf(stderr, "UFFDIO_ZEROPAGE unexpected %Ld\n",
 				uffdio_zeropage.zeropage), exit(1);
-		} else
+		} else {
+			if (test_uffdio_zeropage_eexist) {
+				test_uffdio_zeropage_eexist = false;
+				retry_uffdio_zeropage(ufd, &uffdio_zeropage,
+						      offset);
+			}
 			return 1;
+		}
 	} else {
 		fprintf(stderr,
 			"UFFDIO_ZEROPAGE succeeded %Ld\n",
@@ -761,7 +910,7 @@ static int userfaultfd_events_test(void)
 		perror("fork"), exit(1);
 
 	if (!pid)
-		return faulting_process();
+		return faulting_process(0);
 
 	waitpid(pid, &err, 0);
 	if (err)
@@ -778,6 +927,72 @@ static int userfaultfd_events_test(void)
 	return userfaults != nr_pages;
 }
 
+static int userfaultfd_sig_test(void)
+{
+	struct uffdio_register uffdio_register;
+	unsigned long expected_ioctls;
+	unsigned long userfaults;
+	pthread_t uffd_mon;
+	int err, features;
+	pid_t pid;
+	char c;
+
+	printf("testing signal delivery: ");
+	fflush(stdout);
+
+	if (uffd_test_ops->release_pages(area_dst))
+		return 1;
+
+	features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
+	if (userfaultfd_open(features) < 0)
+		return 1;
+	fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
+
+	uffdio_register.range.start = (unsigned long) area_dst;
+	uffdio_register.range.len = nr_pages * page_size;
+	uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+	if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+		fprintf(stderr, "register failure\n"), exit(1);
+
+	expected_ioctls = uffd_test_ops->expected_ioctls;
+	if ((uffdio_register.ioctls & expected_ioctls) !=
+	    expected_ioctls)
+		fprintf(stderr,
+			"unexpected missing ioctl for anon memory\n"),
+			exit(1);
+
+	if (faulting_process(1))
+		fprintf(stderr, "faulting process failed\n"), exit(1);
+
+	if (uffd_test_ops->release_pages(area_dst))
+		return 1;
+
+	if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, NULL))
+		perror("uffd_poll_thread create"), exit(1);
+
+	pid = fork();
+	if (pid < 0)
+		perror("fork"), exit(1);
+
+	if (!pid)
+		exit(faulting_process(2));
+
+	waitpid(pid, &err, 0);
+	if (err)
+		fprintf(stderr, "faulting process failed\n"), exit(1);
+
+	if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
+		perror("pipe write"), exit(1);
+	if (pthread_join(uffd_mon, (void **)&userfaults))
+		return 1;
+
+	printf("done.\n");
+	if (userfaults)
+		fprintf(stderr, "Signal test failed, userfaults: %ld\n",
+			userfaults);
+	close(uffd);
+	return userfaults != 0;
+}
 static int userfaultfd_stress(void)
 {
 	void *area;
@@ -879,6 +1094,15 @@ static int userfaultfd_stress(void)
 			return 1;
 		}
 
+		if (area_dst_alias) {
+			uffdio_register.range.start = (unsigned long)
+				area_dst_alias;
+			if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
+				fprintf(stderr, "register failure alias\n");
+				return 1;
+			}
+		}
+
 		/*
 		 * The madvise done previously isn't enough: some
 		 * uffd_thread could have read userfaults (one of
@@ -912,9 +1136,17 @@ static int userfaultfd_stress(void)
 
 		/* unregister */
 		if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range)) {
-			fprintf(stderr, "register failure\n");
+			fprintf(stderr, "unregister failure\n");
 			return 1;
 		}
+		if (area_dst_alias) {
+			uffdio_register.range.start = (unsigned long) area_dst;
+			if (ioctl(uffd, UFFDIO_UNREGISTER,
+				  &uffdio_register.range)) {
+				fprintf(stderr, "unregister failure alias\n");
+				return 1;
+			}
+		}
 
 		/* verification */
 		if (bounces & BOUNCE_VERIFY) {
@@ -936,6 +1168,10 @@ static int userfaultfd_stress(void)
 		area_src = area_dst;
 		area_dst = tmp_area;
 
+		tmp_area = area_src_alias;
+		area_src_alias = area_dst_alias;
+		area_dst_alias = tmp_area;
+
 		printf("userfaults:");
 		for (cpu = 0; cpu < nr_cpus; cpu++)
 			printf(" %lu", userfaults[cpu]);
@@ -946,7 +1182,8 @@ static int userfaultfd_stress(void)
 		return err;
 
 	close(uffd);
-	return userfaultfd_zeropage_test() || userfaultfd_events_test();
+	return userfaultfd_zeropage_test() || userfaultfd_sig_test()
+		|| userfaultfd_events_test();
 }
 
 /*
@@ -981,7 +1218,12 @@ static void set_test_type(const char *type)
 	} else if (!strcmp(type, "hugetlb")) {
 		test_type = TEST_HUGETLB;
 		uffd_test_ops = &hugetlb_uffd_test_ops;
+	} else if (!strcmp(type, "hugetlb_shared")) {
+		map_shared = true;
+		test_type = TEST_HUGETLB;
+		uffd_test_ops = &hugetlb_uffd_test_ops;
 	} else if (!strcmp(type, "shmem")) {
+		map_shared = true;
 		test_type = TEST_SHMEM;
 		uffd_test_ops = &shmem_uffd_test_ops;
 	} else {
@@ -1001,12 +1243,25 @@ static void set_test_type(const char *type)
 		fprintf(stderr, "Impossible to run this test\n"), exit(2);
 }
 
+static void sigalrm(int sig)
+{
+	if (sig != SIGALRM)
+		abort();
+	test_uffdio_copy_eexist = true;
+	test_uffdio_zeropage_eexist = true;
+	alarm(ALARM_INTERVAL_SECS);
+}
+
 int main(int argc, char **argv)
 {
 	if (argc < 4)
 		fprintf(stderr, "Usage: <test type> <MiB> <bounces> [hugetlbfs_file]\n"),
 				exit(1);
 
+	if (signal(SIGALRM, sigalrm) == SIG_ERR)
+		fprintf(stderr, "failed to arm SIGALRM"), exit(1);
+	alarm(ALARM_INTERVAL_SECS);
+
 	set_test_type(argv[1]);
 
 	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);