userfaultfd/selftests: unify error handling
authorPeter Xu <peterx@redhat.com>
Thu, 1 Jul 2021 01:48:55 +0000 (18:48 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 1 Jul 2021 03:47:27 +0000 (20:47 -0700)
Introduce err()/_err() and replace all the different ways to fail the
program, mostly "fprintf" and "perror" with tons of exit() calls.  Always
stop the test program at any failure.

Link: https://lkml.kernel.org/r/20210412232753.1012412-6-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Wang Qing <wangqing@vivo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
tools/testing/selftests/vm/userfaultfd.c

index da2374b..6339aea 100644 (file)
@@ -140,11 +140,18 @@ static void usage(void)
        exit(1);
 }
 
-#define uffd_error(code, fmt, ...)                                             \
-       do {                                                                   \
-               fprintf(stderr, fmt, ##__VA_ARGS__);                           \
-               fprintf(stderr, ": %" PRId64 "\n", (int64_t)(code));           \
-               exit(1);                                                       \
+#define _err(fmt, ...)                                         \
+       do {                                                    \
+               int ret = errno;                                \
+               fprintf(stderr, "ERROR: " fmt, ##__VA_ARGS__);  \
+               fprintf(stderr, " (errno=%d, line=%d)\n",       \
+                       ret, __LINE__);                         \
+       } while (0)
+
+#define err(fmt, ...)                          \
+       do {                                    \
+               _err(fmt, ##__VA_ARGS__);       \
+               exit(1);                        \
        } while (0)
 
 static void uffd_stats_reset(struct uffd_stats *uffd_stats,
@@ -193,44 +200,28 @@ static void uffd_stats_report(struct uffd_stats *stats, int n_cpus)
        printf("\n");
 }
 
-static int anon_release_pages(char *rel_area)
+static void anon_release_pages(char *rel_area)
 {
-       int ret = 0;
-
-       if (madvise(rel_area, nr_pages * page_size, MADV_DONTNEED)) {
-               perror("madvise");
-               ret = 1;
-       }
-
-       return ret;
+       if (madvise(rel_area, nr_pages * page_size, MADV_DONTNEED))
+               err("madvise(MADV_DONTNEED) failed");
 }
 
 static void anon_allocate_area(void **alloc_area)
 {
-       if (posix_memalign(alloc_area, page_size, nr_pages * page_size)) {
-               fprintf(stderr, "out of memory\n");
-               *alloc_area = NULL;
-       }
+       if (posix_memalign(alloc_area, page_size, nr_pages * page_size))
+               err("posix_memalign() failed");
 }
 
 static void noop_alias_mapping(__u64 *start, size_t len, unsigned long offset)
 {
 }
 
-/* HugeTLB memory */
-static int hugetlb_release_pages(char *rel_area)
+static void hugetlb_release_pages(char *rel_area)
 {
-       int ret = 0;
-
        if (fallocate(huge_fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
-                               rel_area == huge_fd_off0 ? 0 :
-                               nr_pages * page_size,
-                               nr_pages * page_size)) {
-               perror("fallocate");
-               ret = 1;
-       }
-
-       return ret;
+                     rel_area == huge_fd_off0 ? 0 : nr_pages * page_size,
+                     nr_pages * page_size))
+               err("fallocate() failed");
 }
 
 static void hugetlb_allocate_area(void **alloc_area)
@@ -243,20 +234,16 @@ static void hugetlb_allocate_area(void **alloc_area)
                           MAP_HUGETLB,
                           huge_fd, *alloc_area == area_src ? 0 :
                           nr_pages * page_size);
-       if (*alloc_area == MAP_FAILED) {
-               perror("mmap of hugetlbfs file failed");
-               goto fail;
-       }
+       if (*alloc_area == MAP_FAILED)
+               err("mmap of hugetlbfs file failed");
 
        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) {
-                       perror("mmap of hugetlb file alias failed");
-                       goto fail_munmap;
-               }
+               if (area_alias == MAP_FAILED)
+                       err("mmap of hugetlb file alias failed");
        }
 
        if (*alloc_area == area_src) {
@@ -267,16 +254,6 @@ static void hugetlb_allocate_area(void **alloc_area)
        }
        if (area_alias)
                *alloc_area_alias = area_alias;
-
-       return;
-
-fail_munmap:
-       if (munmap(*alloc_area, nr_pages * page_size) < 0) {
-               perror("hugetlb munmap");
-               exit(1);
-       }
-fail:
-       *alloc_area = NULL;
 }
 
 static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset)
@@ -292,33 +269,24 @@ static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset
        *start = (unsigned long) area_dst_alias + offset;
 }
 
-/* Shared memory */
-static int shmem_release_pages(char *rel_area)
+static void shmem_release_pages(char *rel_area)
 {
-       int ret = 0;
-
-       if (madvise(rel_area, nr_pages * page_size, MADV_REMOVE)) {
-               perror("madvise");
-               ret = 1;
-       }
-
-       return ret;
+       if (madvise(rel_area, nr_pages * page_size, MADV_REMOVE))
+               err("madvise(MADV_REMOVE) failed");
 }
 
 static void shmem_allocate_area(void **alloc_area)
 {
        *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
                           MAP_ANONYMOUS | MAP_SHARED, -1, 0);
-       if (*alloc_area == MAP_FAILED) {
-               fprintf(stderr, "shared memory mmap failed\n");
-               *alloc_area = NULL;
-       }
+       if (*alloc_area == MAP_FAILED)
+               err("mmap of memfd failed");
 }
 
 struct uffd_test_ops {
        unsigned long expected_ioctls;
        void (*allocate_area)(void **alloc_area);
-       int (*release_pages)(char *rel_area);
+       void (*release_pages)(char *rel_area);
        void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset);
 };
 
@@ -373,11 +341,8 @@ static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
        /* Undo write-protect, do wakeup after that */
        prms.mode = wp ? UFFDIO_WRITEPROTECT_MODE_WP : 0;
 
-       if (ioctl(ufd, UFFDIO_WRITEPROTECT, &prms)) {
-               fprintf(stderr, "clear WP failed for address 0x%" PRIx64 "\n",
-                       (uint64_t)start);
-               exit(1);
-       }
+       if (ioctl(ufd, UFFDIO_WRITEPROTECT, &prms))
+               err("clear WP failed: address=0x%"PRIx64, (uint64_t)start);
 }
 
 static void continue_range(int ufd, __u64 start, __u64 len)
@@ -388,12 +353,9 @@ static void continue_range(int ufd, __u64 start, __u64 len)
        req.range.len = len;
        req.mode = 0;
 
-       if (ioctl(ufd, UFFDIO_CONTINUE, &req)) {
-               fprintf(stderr,
-                       "UFFDIO_CONTINUE failed for address 0x%" PRIx64 "\n",
-                       (uint64_t)start);
-               exit(1);
-       }
+       if (ioctl(ufd, UFFDIO_CONTINUE, &req))
+               err("UFFDIO_CONTINUE failed for address 0x%" PRIx64,
+                   (uint64_t)start);
 }
 
 static void *locking_thread(void *arg)
@@ -412,10 +374,8 @@ static void *locking_thread(void *arg)
                        seed += cpu;
                bzero(&rand, sizeof(rand));
                bzero(&randstate, sizeof(randstate));
-               if (initstate_r(seed, randstate, sizeof(randstate), &rand)) {
-                       fprintf(stderr, "srandom_r error\n");
-                       exit(1);
-               }
+               if (initstate_r(seed, randstate, sizeof(randstate), &rand))
+                       err("initstate_r failed");
        } else {
                page_nr = -bounces;
                if (!(bounces & BOUNCE_RACINGFAULTS))
@@ -424,16 +384,12 @@ static void *locking_thread(void *arg)
 
        while (!finished) {
                if (bounces & BOUNCE_RANDOM) {
-                       if (random_r(&rand, &rand_nr)) {
-                               fprintf(stderr, "random_r 1 error\n");
-                               exit(1);
-                       }
+                       if (random_r(&rand, &rand_nr))
+                               err("random_r failed");
                        page_nr = rand_nr;
                        if (sizeof(page_nr) > sizeof(rand_nr)) {
-                               if (random_r(&rand, &rand_nr)) {
-                                       fprintf(stderr, "random_r 2 error\n");
-                                       exit(1);
-                               }
+                               if (random_r(&rand, &rand_nr))
+                                       err("random_r failed");
                                page_nr |= (((unsigned long) rand_nr) << 16) <<
                                           16;
                        }
@@ -442,12 +398,9 @@ static void *locking_thread(void *arg)
                page_nr %= nr_pages;
                pthread_mutex_lock(area_mutex(area_dst, page_nr));
                count = *area_count(area_dst, page_nr);
-               if (count != count_verify[page_nr]) {
-                       fprintf(stderr,
-                               "page_nr %lu memory corruption %Lu %Lu\n",
-                               page_nr, count,
-                               count_verify[page_nr]); exit(1);
-               }
+               if (count != count_verify[page_nr])
+                       err("page_nr %lu memory corruption %llu %llu",
+                           page_nr, count, count_verify[page_nr]);
                count++;
                *area_count(area_dst, page_nr) = count_verify[page_nr] = count;
                pthread_mutex_unlock(area_mutex(area_dst, page_nr));
@@ -464,22 +417,21 @@ static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy,
                                     offset);
        if (ioctl(ufd, UFFDIO_COPY, uffdio_copy)) {
                /* real retval in ufdio_copy.copy */
-               if (uffdio_copy->copy != -EEXIST) {
-                       uffd_error(uffdio_copy->copy,
-                                  "UFFDIO_COPY retry error");
-               }
-       } else
-               uffd_error(uffdio_copy->copy, "UFFDIO_COPY retry unexpected");
+               if (uffdio_copy->copy != -EEXIST)
+                       err("UFFDIO_COPY retry error: %"PRId64,
+                           (int64_t)uffdio_copy->copy);
+       } else {
+               err("UFFDIO_COPY retry unexpected: %"PRId64,
+                   (int64_t)uffdio_copy->copy);
+       }
 }
 
 static int __copy_page(int ufd, unsigned long offset, bool retry)
 {
        struct uffdio_copy uffdio_copy;
 
-       if (offset >= nr_pages * page_size) {
-               fprintf(stderr, "unexpected offset %lu\n", offset);
-               exit(1);
-       }
+       if (offset >= nr_pages * page_size)
+               err("unexpected offset %lu\n", offset);
        uffdio_copy.dst = (unsigned long) area_dst + offset;
        uffdio_copy.src = (unsigned long) area_src + offset;
        uffdio_copy.len = page_size;
@@ -491,9 +443,10 @@ static int __copy_page(int ufd, unsigned long offset, bool retry)
        if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) {
                /* real retval in ufdio_copy.copy */
                if (uffdio_copy.copy != -EEXIST)
-                       uffd_error(uffdio_copy.copy, "UFFDIO_COPY error");
+                       err("UFFDIO_COPY error: %"PRId64,
+                           (int64_t)uffdio_copy.copy);
        } else if (uffdio_copy.copy != page_size) {
-               uffd_error(uffdio_copy.copy, "UFFDIO_COPY unexpected copy");
+               err("UFFDIO_COPY error: %"PRId64, (int64_t)uffdio_copy.copy);
        } else {
                if (test_uffdio_copy_eexist && retry) {
                        test_uffdio_copy_eexist = false;
@@ -522,11 +475,10 @@ static int uffd_read_msg(int ufd, struct uffd_msg *msg)
                if (ret < 0) {
                        if (errno == EAGAIN)
                                return 1;
-                       perror("blocking read error");
+                       err("blocking read error");
                } else {
-                       fprintf(stderr, "short read\n");
+                       err("short read");
                }
-               exit(1);
        }
 
        return 0;
@@ -537,10 +489,8 @@ static void uffd_handle_page_fault(struct uffd_msg *msg,
 {
        unsigned long offset;
 
-       if (msg->event != UFFD_EVENT_PAGEFAULT) {
-               fprintf(stderr, "unexpected msg event %u\n", msg->event);
-               exit(1);
-       }
+       if (msg->event != UFFD_EVENT_PAGEFAULT)
+               err("unexpected msg event %u", msg->event);
 
        if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WP) {
                /* Write protect page faults */
@@ -571,10 +521,8 @@ static void uffd_handle_page_fault(struct uffd_msg *msg,
                stats->minor_faults++;
        } else {
                /* Missing page faults */
-               if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE) {
-                       fprintf(stderr, "unexpected write fault\n");
-                       exit(1);
-               }
+               if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
+                       err("unexpected write fault");
 
                offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst;
                offset &= ~(page_size-1);
@@ -601,32 +549,20 @@ static void *uffd_poll_thread(void *arg)
 
        for (;;) {
                ret = poll(pollfd, 2, -1);
-               if (!ret) {
-                       fprintf(stderr, "poll error %d\n", ret);
-                       exit(1);
-               }
-               if (ret < 0) {
-                       perror("poll");
-                       exit(1);
-               }
+               if (ret <= 0)
+                       err("poll error: %d", ret);
                if (pollfd[1].revents & POLLIN) {
-                       if (read(pollfd[1].fd, &tmp_chr, 1) != 1) {
-                               fprintf(stderr, "read pipefd error\n");
-                               exit(1);
-                       }
+                       if (read(pollfd[1].fd, &tmp_chr, 1) != 1)
+                               err("read pipefd error");
                        break;
                }
-               if (!(pollfd[0].revents & POLLIN)) {
-                       fprintf(stderr, "pollfd[0].revents %d\n",
-                               pollfd[0].revents);
-                       exit(1);
-               }
+               if (!(pollfd[0].revents & POLLIN))
+                       err("pollfd[0].revents %d", pollfd[0].revents);
                if (uffd_read_msg(uffd, &msg))
                        continue;
                switch (msg.event) {
                default:
-                       fprintf(stderr, "unexpected msg event %u\n",
-                               msg.event); exit(1);
+                       err("unexpected msg event %u\n", msg.event);
                        break;
                case UFFD_EVENT_PAGEFAULT:
                        uffd_handle_page_fault(&msg, stats);
@@ -640,10 +576,8 @@ static void *uffd_poll_thread(void *arg)
                        uffd_reg.range.start = msg.arg.remove.start;
                        uffd_reg.range.len = msg.arg.remove.end -
                                msg.arg.remove.start;
-                       if (ioctl(uffd, UFFDIO_UNREGISTER, &uffd_reg.range)) {
-                               fprintf(stderr, "remove failure\n");
-                               exit(1);
-                       }
+                       if (ioctl(uffd, UFFDIO_UNREGISTER, &uffd_reg.range))
+                               err("remove failure");
                        break;
                case UFFD_EVENT_REMAP:
                        area_dst = (char *)(unsigned long)msg.arg.remap.to;
@@ -746,9 +680,7 @@ static int stress(struct uffd_stats *uffd_stats)
         * UFFDIO_COPY without writing zero pages into area_dst
         * because the background threads already completed).
         */
-       if (uffd_test_ops->release_pages(area_src))
-               return 1;
-
+       uffd_test_ops->release_pages(area_src);
 
        finished = 1;
        for (cpu = 0; cpu < nr_cpus; cpu++)
@@ -758,10 +690,8 @@ static int stress(struct uffd_stats *uffd_stats)
        for (cpu = 0; cpu < nr_cpus; cpu++) {
                char c;
                if (bounces & BOUNCE_POLL) {
-                       if (write(pipefd[cpu*2+1], &c, 1) != 1) {
-                               fprintf(stderr, "pipefd write error\n");
-                               return 1;
-                       }
+                       if (write(pipefd[cpu*2+1], &c, 1) != 1)
+                               err("pipefd write error");
                        if (pthread_join(uffd_threads[cpu],
                                         (void *)&uffd_stats[cpu]))
                                return 1;
@@ -861,10 +791,8 @@ static int faulting_process(int signal_test)
                memset(&act, 0, sizeof(act));
                act.sa_sigaction = sighndl;
                act.sa_flags = SA_SIGINFO;
-               if (sigaction(SIGBUS, &act, 0)) {
-                       perror("sigaction");
-                       return 1;
-               }
+               if (sigaction(SIGBUS, &act, 0))
+                       err("sigaction");
                lastnr = (unsigned long)-1;
        }
 
@@ -874,10 +802,8 @@ static int faulting_process(int signal_test)
 
                if (signal_test) {
                        if (sigsetjmp(*sigbuf, 1) != 0) {
-                               if (steps == 1 && nr == lastnr) {
-                                       fprintf(stderr, "Signal repeated\n");
-                                       return 1;
-                               }
+                               if (steps == 1 && nr == lastnr)
+                                       err("Signal repeated");
 
                                lastnr = nr;
                                if (signal_test == 1) {
@@ -902,12 +828,9 @@ static int faulting_process(int signal_test)
                }
 
                count = *area_count(area_dst, nr);
-               if (count != count_verify[nr]) {
-                       fprintf(stderr,
-                               "nr %lu memory corruption %Lu %Lu\n",
-                               nr, count,
-                               count_verify[nr]);
-               }
+               if (count != count_verify[nr])
+                       err("nr %lu memory corruption %llu %llu\n",
+                           nr, count, count_verify[nr]);
                /*
                 * Trigger write protection if there is by writing
                 * the same value back.
@@ -923,18 +846,14 @@ static int faulting_process(int signal_test)
 
        area_dst = mremap(area_dst, nr_pages * page_size,  nr_pages * page_size,
                          MREMAP_MAYMOVE | MREMAP_FIXED, area_src);
-       if (area_dst == MAP_FAILED) {
-               perror("mremap");
-               exit(1);
-       }
+       if (area_dst == MAP_FAILED)
+               err("mremap");
 
        for (; nr < nr_pages; nr++) {
                count = *area_count(area_dst, nr);
                if (count != count_verify[nr]) {
-                       fprintf(stderr,
-                               "nr %lu memory corruption %Lu %Lu\n",
-                               nr, count,
-                               count_verify[nr]); exit(1);
+                       err("nr %lu memory corruption %llu %llu\n",
+                           nr, count, count_verify[nr]);
                }
                /*
                 * Trigger write protection if there is by writing
@@ -943,15 +862,11 @@ static int faulting_process(int signal_test)
                *area_count(area_dst, nr) = count;
        }
 
-       if (uffd_test_ops->release_pages(area_dst))
-               return 1;
+       uffd_test_ops->release_pages(area_dst);
 
-       for (nr = 0; nr < nr_pages; nr++) {
-               if (my_bcmp(area_dst + nr * page_size, zeropage, page_size)) {
-                       fprintf(stderr, "nr %lu is not zero\n", nr);
-                       exit(1);
-               }
-       }
+       for (nr = 0; nr < nr_pages; nr++)
+               if (my_bcmp(area_dst + nr * page_size, zeropage, page_size))
+                       err("nr %lu is not zero", nr);
 
        return 0;
 }
@@ -964,13 +879,12 @@ static void retry_uffdio_zeropage(int ufd,
                                     uffdio_zeropage->range.len,
                                     offset);
        if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
-               if (uffdio_zeropage->zeropage != -EEXIST) {
-                       uffd_error(uffdio_zeropage->zeropage,
-                                  "UFFDIO_ZEROPAGE retry error");
-               }
+               if (uffdio_zeropage->zeropage != -EEXIST)
+                       err("UFFDIO_ZEROPAGE error: %"PRId64,
+                           (int64_t)uffdio_zeropage->zeropage);
        } else {
-               uffd_error(uffdio_zeropage->zeropage,
-                          "UFFDIO_ZEROPAGE retry unexpected");
+               err("UFFDIO_ZEROPAGE error: %"PRId64,
+                   (int64_t)uffdio_zeropage->zeropage);
        }
 }
 
@@ -983,10 +897,8 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
 
        has_zeropage = uffd_test_ops->expected_ioctls & (1 << _UFFDIO_ZEROPAGE);
 
-       if (offset >= nr_pages * page_size) {
-               fprintf(stderr, "unexpected offset %lu\n", offset);
-               exit(1);
-       }
+       if (offset >= nr_pages * page_size)
+               err("unexpected offset %lu", offset);
        uffdio_zeropage.range.start = (unsigned long) area_dst + offset;
        uffdio_zeropage.range.len = page_size;
        uffdio_zeropage.mode = 0;
@@ -994,14 +906,13 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
        res = uffdio_zeropage.zeropage;
        if (ret) {
                /* real retval in ufdio_zeropage.zeropage */
-               if (has_zeropage) {
-                       uffd_error(res, "UFFDIO_ZEROPAGE %s",
-                                  res == -EEXIST ? "-EEXIST" : "error");
-               } else if (res != -EINVAL)
-                       uffd_error(res, "UFFDIO_ZEROPAGE not -EINVAL");
+               if (has_zeropage)
+                       err("UFFDIO_ZEROPAGE error: %"PRId64, (int64_t)res);
+               else if (res != -EINVAL)
+                       err("UFFDIO_ZEROPAGE not -EINVAL");
        } else if (has_zeropage) {
                if (res != page_size) {
-                       uffd_error(res, "UFFDIO_ZEROPAGE unexpected");
+                       err("UFFDIO_ZEROPAGE unexpected size");
                } else {
                        if (test_uffdio_zeropage_eexist && retry) {
                                test_uffdio_zeropage_eexist = false;
@@ -1011,7 +922,7 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
                        return 1;
                }
        } else
-               uffd_error(res, "UFFDIO_ZEROPAGE succeeded");
+               err("UFFDIO_ZEROPAGE succeeded");
 
        return 0;
 }
@@ -1030,8 +941,7 @@ static int userfaultfd_zeropage_test(void)
        printf("testing UFFDIO_ZEROPAGE: ");
        fflush(stdout);
 
-       if (uffd_test_ops->release_pages(area_dst))
-               return 1;
+       uffd_test_ops->release_pages(area_dst);
 
        if (userfaultfd_open(0))
                return 1;
@@ -1040,25 +950,16 @@ static int userfaultfd_zeropage_test(void)
        uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
        if (test_uffdio_wp)
                uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
-       if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
-               fprintf(stderr, "register failure\n");
-               exit(1);
-       }
+       if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+               err("register failure");
 
        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 ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls)
+               err("unexpected missing ioctl for anon memory");
 
-       if (uffdio_zeropage(uffd, 0)) {
-               if (my_bcmp(area_dst, zeropage, page_size)) {
-                       fprintf(stderr, "zeropage is not zero\n");
-                       exit(1);
-               }
-       }
+       if (uffdio_zeropage(uffd, 0))
+               if (my_bcmp(area_dst, zeropage, page_size))
+                       err("zeropage is not zero");
 
        close(uffd);
        printf("done.\n");
@@ -1078,8 +979,7 @@ static int userfaultfd_events_test(void)
        printf("testing events (fork, remap, remove): ");
        fflush(stdout);
 
-       if (uffd_test_ops->release_pages(area_dst))
-               return 1;
+       uffd_test_ops->release_pages(area_dst);
 
        features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
                UFFD_FEATURE_EVENT_REMOVE;
@@ -1092,41 +992,28 @@ static int userfaultfd_events_test(void)
        uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
        if (test_uffdio_wp)
                uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
-       if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
-               fprintf(stderr, "register failure\n");
-               exit(1);
-       }
+       if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+               err("register failure");
 
        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 ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls)
+               err("unexpected missing ioctl for anon memory");
 
-       if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats)) {
-               perror("uffd_poll_thread create");
-               exit(1);
-       }
+       if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
+               err("uffd_poll_thread create");
 
        pid = fork();
-       if (pid < 0) {
-               perror("fork");
-               exit(1);
-       }
+       if (pid < 0)
+               err("fork");
 
        if (!pid)
                exit(faulting_process(0));
 
        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 (err)
+               err("faulting process failed");
+       if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
+               err("pipe write");
        if (pthread_join(uffd_mon, NULL))
                return 1;
 
@@ -1151,8 +1038,7 @@ static int userfaultfd_sig_test(void)
        printf("testing signal delivery: ");
        fflush(stdout);
 
-       if (uffd_test_ops->release_pages(area_dst))
-               return 1;
+       uffd_test_ops->release_pages(area_dst);
 
        features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
        if (userfaultfd_open(features))
@@ -1164,57 +1050,41 @@ static int userfaultfd_sig_test(void)
        uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
        if (test_uffdio_wp)
                uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
-       if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
-               fprintf(stderr, "register failure\n");
-               exit(1);
-       }
+       if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+               err("register failure");
 
        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 ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls)
+               err("unexpected missing ioctl for anon memory");
 
-       if (faulting_process(1)) {
-               fprintf(stderr, "faulting process failed\n");
-               exit(1);
-       }
+       if (faulting_process(1))
+               err("faulting process failed");
 
-       if (uffd_test_ops->release_pages(area_dst))
-               return 1;
+       uffd_test_ops->release_pages(area_dst);
 
-       if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats)) {
-               perror("uffd_poll_thread create");
-               exit(1);
-       }
+       if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
+               err("uffd_poll_thread create");
 
        pid = fork();
-       if (pid < 0) {
-               perror("fork");
-               exit(1);
-       }
+       if (pid < 0)
+               err("fork");
 
        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 (err)
+               err("faulting process failed");
+       if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
+               err("pipe write");
        if (pthread_join(uffd_mon, (void **)&userfaults))
                return 1;
 
        printf("done.\n");
        if (userfaults)
-               fprintf(stderr, "Signal test failed, userfaults: %ld\n",
-                       userfaults);
+               err("Signal test failed, userfaults: %ld", userfaults);
        close(uffd);
+
        return userfaults != 0;
 }
 
@@ -1236,8 +1106,7 @@ static int userfaultfd_minor_test(void)
        printf("testing minor faults: ");
        fflush(stdout);
 
-       if (uffd_test_ops->release_pages(area_dst))
-               return 1;
+       uffd_test_ops->release_pages(area_dst);
 
        if (userfaultfd_open_ext(&features))
                return 1;
@@ -1251,17 +1120,13 @@ static int userfaultfd_minor_test(void)
        uffdio_register.range.start = (unsigned long)area_dst_alias;
        uffdio_register.range.len = nr_pages * page_size;
        uffdio_register.mode = UFFDIO_REGISTER_MODE_MINOR;
-       if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
-               fprintf(stderr, "register failure\n");
-               exit(1);
-       }
+       if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+               err("register failure");
 
        expected_ioctls = uffd_test_ops->expected_ioctls;
        expected_ioctls |= 1 << _UFFDIO_CONTINUE;
-       if ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls) {
-               fprintf(stderr, "unexpected missing ioctl(s)\n");
-               exit(1);
-       }
+       if ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls)
+               err("unexpected missing ioctl(s)");
 
        /*
         * After registering with UFFD, populate the non-UFFD-registered side of
@@ -1272,10 +1137,8 @@ static int userfaultfd_minor_test(void)
                       page_size);
        }
 
-       if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats)) {
-               perror("uffd_poll_thread create");
-               exit(1);
-       }
+       if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
+               err("uffd_poll_thread create");
 
        /*
         * Read each of the pages back using the UFFD-registered mapping. We
@@ -1284,26 +1147,19 @@ static int userfaultfd_minor_test(void)
         * page's contents, and then issuing a CONTINUE ioctl.
         */
 
-       if (posix_memalign(&expected_page, page_size, page_size)) {
-               fprintf(stderr, "out of memory\n");
-               return 1;
-       }
+       if (posix_memalign(&expected_page, page_size, page_size))
+               err("out of memory");
 
        for (p = 0; p < nr_pages; ++p) {
                expected_byte = ~((uint8_t)(p % ((uint8_t)-1)));
                memset(expected_page, expected_byte, page_size);
                if (my_bcmp(expected_page, area_dst_alias + (p * page_size),
-                           page_size)) {
-                       fprintf(stderr,
-                               "unexpected page contents after minor fault\n");
-                       exit(1);
-               }
+                           page_size))
+                       err("unexpected page contents after minor fault");
        }
 
-       if (write(pipefd[1], &c, sizeof(c)) != sizeof(c)) {
-               perror("pipe write");
-               exit(1);
-       }
+       if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
+               err("pipe write");
        if (pthread_join(uffd_mon, NULL))
                return 1;
 
@@ -1321,7 +1177,6 @@ static int userfaultfd_stress(void)
        unsigned long nr;
        struct uffdio_register uffdio_register;
        unsigned long cpu;
-       int err;
        struct uffd_stats uffd_stats[nr_cpus];
 
        uffd_test_ops->allocate_area((void **)&area_src);
@@ -1366,10 +1221,8 @@ static int userfaultfd_stress(void)
                }
        }
 
-       if (posix_memalign(&area, page_size, page_size)) {
-               fprintf(stderr, "out of memory\n");
-               return 1;
-       }
+       if (posix_memalign(&area, page_size, page_size))
+               err("out of memory");
        zeropage = area;
        bzero(zeropage, page_size);
 
@@ -1378,7 +1231,6 @@ static int userfaultfd_stress(void)
        pthread_attr_init(&attr);
        pthread_attr_setstacksize(&attr, 16*1024*1024);
 
-       err = 0;
        while (bounces--) {
                unsigned long expected_ioctls;
 
@@ -1407,25 +1259,18 @@ static int userfaultfd_stress(void)
                uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
                if (test_uffdio_wp)
                        uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
-               if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
-                       fprintf(stderr, "register failure\n");
-                       return 1;
-               }
+               if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+                       err("register failure");
                expected_ioctls = uffd_test_ops->expected_ioctls;
                if ((uffdio_register.ioctls & expected_ioctls) !=
-                   expected_ioctls) {
-                       fprintf(stderr,
-                               "unexpected missing ioctl for anon memory\n");
-                       return 1;
-               }
+                   expected_ioctls)
+                       err("unexpected missing ioctl for anon memory");
 
                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;
-                       }
+                       if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+                               err("register failure alias");
                }
 
                /*
@@ -1452,8 +1297,7 @@ static int userfaultfd_stress(void)
                 * MADV_DONTNEED only after the UFFDIO_REGISTER, so it's
                 * required to MADV_DONTNEED here.
                 */
-               if (uffd_test_ops->release_pages(area_dst))
-                       return 1;
+               uffd_test_ops->release_pages(area_dst);
 
                uffd_stats_reset(uffd_stats, nr_cpus);
 
@@ -1467,33 +1311,22 @@ static int userfaultfd_stress(void)
                                 nr_pages * page_size, false);
 
                /* unregister */
-               if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range)) {
-                       fprintf(stderr, "unregister failure\n");
-                       return 1;
-               }
+               if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range))
+                       err("unregister failure");
                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;
-                       }
+                                 &uffdio_register.range))
+                               err("unregister failure alias");
                }
 
                /* verification */
-               if (bounces & BOUNCE_VERIFY) {
-                       for (nr = 0; nr < nr_pages; nr++) {
-                               if (*area_count(area_dst, nr) != count_verify[nr]) {
-                                       fprintf(stderr,
-                                               "error area_count %Lu %Lu %lu\n",
-                                               *area_count(area_src, nr),
-                                               count_verify[nr],
-                                               nr);
-                                       err = 1;
-                                       bounces = 0;
-                               }
-                       }
-               }
+               if (bounces & BOUNCE_VERIFY)
+                       for (nr = 0; nr < nr_pages; nr++)
+                               if (*area_count(area_dst, nr) != count_verify[nr])
+                                       err("error area_count %llu %llu %lu\n",
+                                           *area_count(area_src, nr),
+                                           count_verify[nr], nr);
 
                /* prepare next bounce */
                tmp_area = area_src;
@@ -1507,9 +1340,6 @@ static int userfaultfd_stress(void)
                uffd_stats_report(uffd_stats, nr_cpus);
        }
 
-       if (err)
-               return err;
-
        close(uffd);
        return userfaultfd_zeropage_test() || userfaultfd_sig_test()
                || userfaultfd_events_test() || userfaultfd_minor_test();
@@ -1560,7 +1390,7 @@ static void set_test_type(const char *type)
                test_type = TEST_SHMEM;
                uffd_test_ops = &shmem_uffd_test_ops;
        } else {
-               fprintf(stderr, "Unknown test type: %s\n", type); exit(1);
+               err("Unknown test type: %s", type);
        }
 
        if (test_type == TEST_HUGETLB)
@@ -1568,15 +1398,11 @@ static void set_test_type(const char *type)
        else
                page_size = sysconf(_SC_PAGE_SIZE);
 
-       if (!page_size) {
-               fprintf(stderr, "Unable to determine page size\n");
-               exit(2);
-       }
+       if (!page_size)
+               err("Unable to determine page size");
        if ((unsigned long) area_count(NULL, 0) + sizeof(unsigned long long) * 2
-           > page_size) {
-               fprintf(stderr, "Impossible to run this test\n");
-               exit(2);
-       }
+           > page_size)
+               err("Impossible to run this test");
 }
 
 static void sigalrm(int sig)
@@ -1593,10 +1419,8 @@ int main(int argc, char **argv)
        if (argc < 4)
                usage();
 
-       if (signal(SIGALRM, sigalrm) == SIG_ERR) {
-               fprintf(stderr, "failed to arm SIGALRM");
-               exit(1);
-       }
+       if (signal(SIGALRM, sigalrm) == SIG_ERR)
+               err("failed to arm SIGALRM");
        alarm(ALARM_INTERVAL_SECS);
 
        set_test_type(argv[1]);
@@ -1605,13 +1429,13 @@ int main(int argc, char **argv)
        nr_pages_per_cpu = atol(argv[2]) * 1024*1024 / page_size /
                nr_cpus;
        if (!nr_pages_per_cpu) {
-               fprintf(stderr, "invalid MiB\n");
+               _err("invalid MiB");
                usage();
        }
 
        bounces = atoi(argv[3]);
        if (bounces <= 0) {
-               fprintf(stderr, "invalid bounces\n");
+               _err("invalid bounces");
                usage();
        }
        nr_pages = nr_pages_per_cpu * nr_cpus;
@@ -1620,16 +1444,10 @@ int main(int argc, char **argv)
                if (argc < 5)
                        usage();
                huge_fd = open(argv[4], O_CREAT | O_RDWR, 0755);
-               if (huge_fd < 0) {
-                       fprintf(stderr, "Open of %s failed", argv[3]);
-                       perror("open");
-                       exit(1);
-               }
-               if (ftruncate(huge_fd, 0)) {
-                       fprintf(stderr, "ftruncate %s to size 0 failed", argv[3]);
-                       perror("ftruncate");
-                       exit(1);
-               }
+               if (huge_fd < 0)
+                       err("Open of %s failed", argv[4]);
+               if (ftruncate(huge_fd, 0))
+                       err("ftruncate %s to size 0 failed", argv[4]);
        }
        printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
               nr_pages, nr_pages_per_cpu);