This patch adds tests for UFFD_FEATURE_SIGBUS feature. The tests will verify signal delivery instead of userfault events. Also, test use of UFFDIO_COPY to allocate memory and retry accessing monitored area after signal delivery. This patch also fixes a bug in uffd_poll_thread() where 'uffd' is leaked. Signed-off-by: Prakash Sangappa <prakash.sangappa@xxxxxxxxxx> --- Change log v2: - Added comments to explain the tests. - Fixed test to fail immediately if signal repeats. - Addressed other review comments. v1: https://lkml.org/lkml/2017/7/26/101 --- tools/testing/selftests/vm/userfaultfd.c | 127 +++++++++++++++++++++++++++++- 1 files changed, 124 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index 1eae79a..3976d7a 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -66,6 +66,7 @@ #include <sys/wait.h> #include <pthread.h> #include <linux/userfaultfd.h> +#include <setjmp.h> #ifdef __NR_userfaultfd @@ -408,6 +409,7 @@ static int copy_page(int ufd, unsigned long offset) userfaults++; break; case UFFD_EVENT_FORK: + close(uffd); uffd = msg.arg.fork.ufd; pollfd[0].fd = uffd; break; @@ -572,6 +574,17 @@ 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 +598,59 @@ 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, sig_repeats = 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) { + sig_repeats++; + break; + } + + 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 +660,9 @@ static int faulting_process(void) } } + if (signal_test) + return !(signalled == split_nr_pages && sig_repeats == 0); + if (test_type == TEST_HUGETLB) return 0; @@ -761,7 +817,7 @@ 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 +834,70 @@ 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"); + printf(" Signal test userfaults: %ld\n", userfaults); + close(uffd); + return userfaults != 0; +} static int userfaultfd_stress(void) { void *area; @@ -946,7 +1066,8 @@ 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(); } /* -- 1.7.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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