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 <[email protected]>
---
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
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 <[email protected]>
> ---
> 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 [email protected]. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"[email protected]"> [email protected] </a>
>
--
Sincerely yours,
Mike.
On 7/30/17 12:07 AM, Mike Rapoport wrote:
> 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 <[email protected]>
>> ---
>> 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.
[...]
>> 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.
Ok, sent v3 patch with this change.
Thanks,
-Prakash.