On Thu, Jul 27, 2017 at 10:18:40PM -0400, Prakash Sangappa wrote: > 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 > --- Overall looks good to me, just small nitpick below. > 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++; You can simply 'return 1' here, then sig_repeats variable can be dropped and the return statement for signal_test can be simplified. > + 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. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> > -- Sincerely yours, Mike. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
