[PATCH 24/29] selftests/mm: Move uffd sig/events tests into uffd unit tests

Peter Xu
2023-03-30T16:10:34Z

Move the two tests into the unit test, and convert it into 20 standalone
tests:

- events test on all 5 mem types, with wp on/off
- signal test on all 5 mem types, with wp on/off

Testing sigbus on anon... done
Testing sigbus on shmem... done
Testing sigbus on shmem-private... done
Testing sigbus on hugetlb... done
Testing sigbus on hugetlb-private... done
Testing sigbus-wp on anon... done
Testing sigbus-wp on shmem... done
Testing sigbus-wp on shmem-private... done
Testing sigbus-wp on hugetlb... done
Testing sigbus-wp on hugetlb-private... done
Testing events on anon... done
Testing events on shmem... done
Testing events on shmem-private... done
Testing events on hugetlb... done
Testing events on hugetlb-private... done
Testing events-wp on anon... done
Testing events-wp on shmem... done
Testing events-wp on shmem-private... done
Testing events-wp on hugetlb... done
Testing events-wp on hugetlb-private... done

It'll also remove a lot of global references along the way,
e.g. test_uffdio_wp will be replaced with the wp value passed over.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
tools/testing/selftests/mm/uffd-stress.c | 227 +---------------
tools/testing/selftests/mm/uffd-unit-tests.c | 263 +++++++++++++++++++
2 files changed, 264 insertions(+), 226 deletions(-)

diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
index 49fa61e5c54a..f3046ae13a90 100644
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/tools/testing/selftests/mm/uffd-stress.c
@@ -274,133 +274,6 @@ static int stress(struct uffd_stats *uffd_stats)
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
- * 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 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(int signal_test, bool wp)
-{
- unsigned long nr;
- unsigned long long count;
- unsigned long split_nr_pages;
- unsigned long lastnr;
- struct sigaction act;
- volatile unsigned long signalled = 0;
-
- split_nr_pages = (nr_pages + 1) / 2;
-
- if (signal_test) {
- sigbuf = &jbuf;
- memset(&act, 0, sizeof(act));
- act.sa_sigaction = sighndl;
- act.sa_flags = SA_SIGINFO;
- if (sigaction(SIGBUS, &act, 0))
- err("sigaction");
- lastnr = (unsigned long)-1;
- }
-
- for (nr = 0; nr < split_nr_pages; nr++) {
- volatile int steps = 1;
- unsigned long offset = nr * page_size;
-
- if (signal_test) {
- if (sigsetjmp(*sigbuf, 1) != 0) {
- if (steps == 1 && nr == lastnr)
- err("Signal repeated");
-
- lastnr = nr;
- if (signal_test == 1) {
- if (steps == 1) {
- /* This is a MISSING request */
- steps++;
- if (copy_page(uffd, offset, wp))
- signalled++;
- } else {
- /* This is a WP request */
- assert(steps == 2);
- wp_range(uffd,
- (__u64)area_dst +
- offset,
- page_size, false);
- }
- } else {
- signalled++;
- continue;
- }
- }
- }
-
- count = *area_count(area_dst, 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.
- */
- *area_count(area_dst, nr) = count;
- }
-
- if (signal_test)
- return signalled != split_nr_pages;
-
- area_dst = mremap(area_dst, nr_pages * page_size, nr_pages * page_size,
- MREMAP_MAYMOVE | MREMAP_FIXED, area_src);
- if (area_dst == MAP_FAILED)
- err("mremap");
- /* Reset area_src since we just clobbered it */
- area_src = NULL;
-
- for (; nr < nr_pages; nr++) {
- count = *area_count(area_dst, 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.
- */
- *area_count(area_dst, nr) = count;
- }
-
- 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))
- err("nr %lu is not zero", nr);
-
- return 0;
-}
-
static void retry_uffdio_zeropage(int ufd,
struct uffdio_zeropage *uffdio_zeropage,
unsigned long offset)
@@ -484,103 +357,6 @@ static int userfaultfd_zeropage_test(void)
return 0;
}

-static int userfaultfd_events_test(void)
-{
- pthread_t uffd_mon;
- int err, features;
- pid_t pid;
- char c;
- struct uffd_stats stats = { 0 };
-
- printf("testing events (fork, remap, remove): ");
- fflush(stdout);
-
- features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
- UFFD_FEATURE_EVENT_REMOVE;
- uffd_test_ctx_init(features);
-
- fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
-
- if (uffd_register(uffd, area_dst, nr_pages * page_size,
- true, test_uffdio_wp, false))
- err("register failure");
-
- stats.apply_wp = test_uffdio_wp;
- if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
- err("uffd_poll_thread create");
-
- pid = fork();
- if (pid < 0)
- err("fork");
-
- if (!pid)
- exit(faulting_process(0, test_uffdio_wp));
-
- waitpid(pid, &err, 0);
- 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;
-
- uffd_stats_report(&stats, 1);
-
- return stats.missing_faults != nr_pages;
-}
-
-static int userfaultfd_sig_test(void)
-{
- unsigned long userfaults;
- pthread_t uffd_mon;
- int err, features;
- pid_t pid;
- char c;
- struct uffd_stats stats = { 0 };
-
- printf("testing signal delivery: ");
- fflush(stdout);
-
- features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
- uffd_test_ctx_init(features);
-
- fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
-
- if (uffd_register(uffd, area_dst, nr_pages * page_size,
- true, test_uffdio_wp, false))
- err("register failure");
-
- if (faulting_process(1, test_uffdio_wp))
- err("faulting process failed");
-
- uffd_test_ops->release_pages(area_dst);
-
- stats.apply_wp = test_uffdio_wp;
- if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
- err("uffd_poll_thread create");
-
- pid = fork();
- if (pid < 0)
- err("fork");
-
- if (!pid)
- exit(faulting_process(2, test_uffdio_wp));
-
- waitpid(pid, &err, 0);
- 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)
- err("Signal test failed, userfaults: %ld", userfaults);
-
- return userfaults != 0;
-}
-
static int userfaultfd_stress(void)
{
void *area;
@@ -692,8 +468,7 @@ static int userfaultfd_stress(void)
uffd_stats_report(uffd_stats, nr_cpus);
}

- return userfaultfd_zeropage_test() || userfaultfd_sig_test()
- || userfaultfd_events_test();
+ return userfaultfd_zeropage_test();
}

static void set_test_type(const char *type)
diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c
index ecb8ba658736..ebf45cb0eca8 100644
--- a/tools/testing/selftests/mm/uffd-unit-tests.c
+++ b/tools/testing/selftests/mm/uffd-unit-tests.c
@@ -18,6 +18,9 @@
#define MEM_HUGETLB BIT_ULL(3)
#define MEM_HUGETLB_PRIVATE BIT_ULL(4)

+#define MEM_ALL (MEM_ANON | MEM_SHMEM | MEM_SHMEM_PRIVATE | \
+ MEM_HUGETLB | MEM_HUGETLB_PRIVATE)
+
struct mem_type {
const char *name;
unsigned int mem_flag;
@@ -429,6 +432,237 @@ void uffd_minor_collapse_test(void)
uffd_minor_test_common(true, false);
}

+static 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
+ * 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 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(int signal_test, bool wp)
+{
+ unsigned long nr, i;
+ unsigned long long count;
+ unsigned long split_nr_pages;
+ unsigned long lastnr;
+ struct sigaction act;
+ volatile unsigned long signalled = 0;
+
+ split_nr_pages = (nr_pages + 1) / 2;
+
+ if (signal_test) {
+ sigbuf = &jbuf;
+ memset(&act, 0, sizeof(act));
+ act.sa_sigaction = sighndl;
+ act.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGBUS, &act, 0))
+ err("sigaction");
+ lastnr = (unsigned long)-1;
+ }
+
+ for (nr = 0; nr < split_nr_pages; nr++) {
+ volatile int steps = 1;
+ unsigned long offset = nr * page_size;
+
+ if (signal_test) {
+ if (sigsetjmp(*sigbuf, 1) != 0) {
+ if (steps == 1 && nr == lastnr)
+ err("Signal repeated");
+
+ lastnr = nr;
+ if (signal_test == 1) {
+ if (steps == 1) {
+ /* This is a MISSING request */
+ steps++;
+ if (copy_page(uffd, offset, wp))
+ signalled++;
+ } else {
+ /* This is a WP request */
+ assert(steps == 2);
+ wp_range(uffd,
+ (__u64)area_dst +
+ offset,
+ page_size, false);
+ }
+ } else {
+ signalled++;
+ continue;
+ }
+ }
+ }
+
+ count = *area_count(area_dst, 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.
+ */
+ *area_count(area_dst, nr) = count;
+ }
+
+ if (signal_test)
+ return signalled != split_nr_pages;
+
+ area_dst = mremap(area_dst, nr_pages * page_size, nr_pages * page_size,
+ MREMAP_MAYMOVE | MREMAP_FIXED, area_src);
+ if (area_dst == MAP_FAILED)
+ err("mremap");
+ /* Reset area_src since we just clobbered it */
+ area_src = NULL;
+
+ for (; nr < nr_pages; nr++) {
+ count = *area_count(area_dst, 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.
+ */
+ *area_count(area_dst, nr) = count;
+ }
+
+ uffd_test_ops->release_pages(area_dst);
+
+ for (nr = 0; nr < nr_pages; nr++)
+ for (i = 0; i < page_size; i++)
+ if (*(area_dst + nr * page_size + i) != 0)
+ err("page %lu offset %lu is not zero", nr, i);
+
+ return 0;
+}
+
+static void uffd_sigbus_test_common(bool wp)
+{
+ unsigned long userfaults;
+ pthread_t uffd_mon;
+ pid_t pid;
+ int err;
+ char c;
+ struct uffd_stats stats = { 0 };
+
+ fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
+
+ if (uffd_register(uffd, area_dst, nr_pages * page_size,
+ true, wp, false))
+ err("register failure");
+
+ if (faulting_process(1, wp))
+ err("faulting process failed");
+
+ uffd_test_ops->release_pages(area_dst);
+
+ stats.apply_wp = wp;
+ if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &stats))
+ err("uffd_poll_thread create");
+
+ pid = fork();
+ if (pid < 0)
+ err("fork");
+
+ if (!pid)
+ exit(faulting_process(2, wp));
+
+ waitpid(pid, &err, 0);
+ 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))
+ err("pthread_join()");
+
+ if (userfaults)
+ uffd_test_fail("Signal test failed, userfaults: %ld", userfaults);
+ else
+ uffd_test_pass();
+}
+
+static void uffd_sigbus_test(void)
+{
+ uffd_sigbus_test_common(false);
+}
+
+static void uffd_sigbus_wp_test(void)
+{
+ uffd_sigbus_test_common(true);
+}
+
+static void uffd_events_test_common(bool wp)
+{
+ pthread_t uffd_mon;
+ pid_t pid;
+ int err;
+ char c;
+ struct uffd_stats stats = { 0 };
+
+ fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
+ if (uffd_register(uffd, area_dst, nr_pages * page_size,
+ true, wp, false))
+ err("register failure");
+
+ stats.apply_wp = wp;
+ if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &stats))
+ err("uffd_poll_thread create");
+
+ pid = fork();
+ if (pid < 0)
+ err("fork");
+
+ if (!pid)
+ exit(faulting_process(0, wp));
+
+ waitpid(pid, &err, 0);
+ if (err)
+ err("faulting process failed");
+ if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
+ err("pipe write");
+ if (pthread_join(uffd_mon, NULL))
+ err("pthread_join()");
+
+ if (stats.missing_faults != nr_pages)
+ uffd_test_fail("Fault counts wrong");
+ else
+ uffd_test_pass();
+}
+
+static void uffd_events_test(void)
+{
+ uffd_events_test_common(false);
+}
+
+static void uffd_events_wp_test(void)
+{
+ uffd_events_test_common(true);
+}
+
uffd_test_case_t uffd_tests[] = {
{
.name = "pagemap",
@@ -466,6 +700,35 @@ uffd_test_case_t uffd_tests[] = {
/* We can't test MADV_COLLAPSE, so try our luck */
.uffd_feature_required = UFFD_FEATURE_MINOR_SHMEM,
},
+ {
+ .name = "sigbus",
+ .uffd_fn = uffd_sigbus_test,
+ .mem_targets = MEM_ALL,
+ .uffd_feature_required = UFFD_FEATURE_SIGBUS |
+ UFFD_FEATURE_EVENT_FORK,
+ },
+ {
+ .name = "sigbus-wp",
+ .uffd_fn = uffd_sigbus_wp_test,
+ .mem_targets = MEM_ALL,
+ .uffd_feature_required = UFFD_FEATURE_SIGBUS |
+ UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_PAGEFAULT_FLAG_WP,
+ },
+ {
+ .name = "events",
+ .uffd_fn = uffd_events_test,
+ .mem_targets = MEM_ALL,
+ .uffd_feature_required = UFFD_FEATURE_EVENT_FORK |
+ UFFD_FEATURE_EVENT_REMAP | UFFD_FEATURE_EVENT_REMOVE,
+ },
+ {
+ .name = "events-wp",
+ .uffd_fn = uffd_events_wp_test,
+ .mem_targets = MEM_ALL,
+ .uffd_feature_required = UFFD_FEATURE_EVENT_FORK |
+ UFFD_FEATURE_EVENT_REMAP | UFFD_FEATURE_EVENT_REMOVE |
+ UFFD_FEATURE_PAGEFAULT_FLAG_WP,
+ },
};

int main(int argc, char *argv[])
--
2.39.1