From: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Subject: userfaultfd: non-cooperative: selftest: add test for FORK, MADVDONTNEED and REMAP events Add test for userfaultfd events used in non-cooperative scenario when the process that monitors the userfaultfd and handles user faults is not the same process that causes the page faults. Link: http://lkml.kernel.org/r/20161216144821.5183-41-aarcange@xxxxxxxxxx Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx> Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx> Cc: Michael Rapoport <RAPOPORT@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/vm/userfaultfd.c | 175 +++++++++++++++++++-- 1 file changed, 163 insertions(+), 12 deletions(-) diff -puN tools/testing/selftests/vm/userfaultfd.c~userfaultfd-non-cooperative-selftest-add-test-for-fork-madvdontneed-and-remap-events tools/testing/selftests/vm/userfaultfd.c --- a/tools/testing/selftests/vm/userfaultfd.c~userfaultfd-non-cooperative-selftest-add-test-for-fork-madvdontneed-and-remap-events +++ a/tools/testing/selftests/vm/userfaultfd.c @@ -63,6 +63,7 @@ #include <sys/mman.h> #include <sys/syscall.h> #include <sys/ioctl.h> +#include <sys/wait.h> #include <pthread.h> #include <linux/userfaultfd.h> @@ -347,6 +348,7 @@ static void *uffd_poll_thread(void *arg) unsigned long cpu = (unsigned long) arg; struct pollfd pollfd[2]; struct uffd_msg msg; + struct uffdio_register uffd_reg; int ret; unsigned long offset; char tmp_chr; @@ -378,16 +380,35 @@ static void *uffd_poll_thread(void *arg) continue; perror("nonblocking read error"), exit(1); } - if (msg.event != UFFD_EVENT_PAGEFAULT) + switch (msg.event) { + default: fprintf(stderr, "unexpected msg event %u\n", msg.event), exit(1); - if (msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE) - fprintf(stderr, "unexpected write fault\n"), exit(1); - offset = (char *)(unsigned long)msg.arg.pagefault.address - - area_dst; - offset &= ~(page_size-1); - if (copy_page(uffd, offset)) - userfaults++; + break; + case UFFD_EVENT_PAGEFAULT: + if (msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE) + fprintf(stderr, "unexpected write fault\n"), exit(1); + offset = (char *)(unsigned long)msg.arg.pagefault.address - + area_dst; + offset &= ~(page_size-1); + if (copy_page(uffd, offset)) + userfaults++; + break; + case UFFD_EVENT_FORK: + uffd = msg.arg.fork.ufd; + pollfd[0].fd = uffd; + break; + case UFFD_EVENT_MADVDONTNEED: + uffd_reg.range.start = msg.arg.madv_dn.start; + uffd_reg.range.len = msg.arg.madv_dn.end - + msg.arg.madv_dn.start; + if (ioctl(uffd, UFFDIO_UNREGISTER, &uffd_reg.range)) + fprintf(stderr, "madv_dn failure\n"), exit(1); + break; + case UFFD_EVENT_REMAP: + area_dst = (char *)(unsigned long)msg.arg.remap.to; + break; + } } return (void *)userfaults; } @@ -512,7 +533,7 @@ static int stress(unsigned long *userfau return 0; } -static int userfaultfd_open(void) +static int userfaultfd_open(int features) { struct uffdio_api uffdio_api; @@ -525,7 +546,7 @@ static int userfaultfd_open(void) uffd_flags = fcntl(uffd, F_GETFD, NULL); uffdio_api.api = UFFD_API; - uffdio_api.features = 0; + uffdio_api.features = features; if (ioctl(uffd, UFFDIO_API, &uffdio_api)) { fprintf(stderr, "UFFDIO_API\n"); return 1; @@ -538,6 +559,132 @@ static int userfaultfd_open(void) return 0; } +/* + * For non-cooperative userfaultfd test we fork() a process that will + * generate pagefaults, will mremap the area monitored by the + * userfaultfd and at last this process will release the monitored + * area. + * For the anonymous and shared memory the area is divided into two + * parts, the first part is accessed before mremap, and the second + * part is accessed after mremap. Since hugetlbfs does not support + * mremap, the entire monitored area is accessed in a single pass for + * HUGETLB_TEST. + * The release of the pages currently generates event only for + * anonymous memory (UFFD_EVENT_MADVDONTNEED), hence it is not checked + * for hugetlb and shmem. + */ +static int faulting_process(void) +{ + unsigned long nr; + unsigned long long count; + +#ifndef HUGETLB_TEST + unsigned long split_nr_pages = (nr_pages + 1) / 2; +#else + unsigned long split_nr_pages = nr_pages; +#endif + + for (nr = 0; nr < split_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); + } + } + +#ifndef HUGETLB_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); + + 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); + } + } + +#ifndef SHMEM_TEST + if (release_pages(area_dst)) + return 1; + + 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); + } +#endif /* SHMEM_TEST */ + +#endif /* HUGETLB_TEST */ + + return 0; +} + +static int userfaultfd_events_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 events (fork, remap, madv_dn): "); + fflush(stdout); + + if (release_pages(area_dst)) + return 1; + + features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP | + UFFD_FEATURE_EVENT_MADVDONTNEED; + 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 = EXPECTED_IOCTLS; + if ((uffdio_register.ioctls & expected_ioctls) != + expected_ioctls) + fprintf(stderr, + "unexpected missing ioctl for anon memory\n"), + exit(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) + return faulting_process(); + + 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; + + close(uffd); + printf("userfaults: %ld\n", userfaults); + + return userfaults != nr_pages; +} + static int userfaultfd_stress(void) { void *area; @@ -555,7 +702,7 @@ static int userfaultfd_stress(void) if (!area_dst) return 1; - if (userfaultfd_open() < 0) + if (userfaultfd_open(0) < 0) return 1; count_verify = malloc(nr_pages * sizeof(unsigned long long)); @@ -702,7 +849,11 @@ static int userfaultfd_stress(void) printf("\n"); } - return err; + if (err) + return err; + + close(uffd); + return userfaultfd_events_test(); } #ifndef HUGETLB_TEST _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
