Re: [RESEND PATCH v3 2/2] userfaultfd: selftest: Add tests for UFFD_FEATURE_SIGBUS feature

[Mike Rapoport]

On Mon, Jul 31, 2017 at 09:54:06PM -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 
> ---

Reviewed-by: Mike Rapoport 

> Change log
> 
> v3:  Eliminated use of sig_repeat variable and simplified error return.
> 
> 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..52740ae 100644
> --- a/tools/testing/selftests/vm/userfaultfd.c
> +++ b/tools/testing/selftests/vm/userfaultfd.c
> @@ -66,6 +66,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
> 
>  #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;
> 
>   if (test_type != TEST_HUGETLB)
>   split_nr_pages = (nr_pages + 1) / 2;
>   else
>   split_nr_pages = nr_pages;
> 
> + if (signal_test) {
> + sigbuf = 
> + memset(, 0, sizeof(act));
> + act.sa_sigaction = sighndl;
> + act.sa_flags = SA_SIGINFO;
> + if (sigaction(SIGBUS, , 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) {
> + fprintf(stderr, "Signal repeated\n");
> + return 1;
> + }
> +
> + 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;
> +
>   if (test_type == TEST_HUGETLB)
>   return 0;
> 
> @@ -761,7 +817,7 @@ static int userfaultfd_events_test(void)
>   perror("fork"), exit(1);

Re: [RESEND PATCH v3 2/2] userfaultfd: selftest: Add tests for UFFD_FEATURE_SIGBUS feature

[Mike Rapoport]

On Mon, Jul 31, 2017 at 09:54:06PM -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 
> ---

Reviewed-by: Mike Rapoport 

> Change log
> 
> v3:  Eliminated use of sig_repeat variable and simplified error return.
> 
> 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..52740ae 100644
> --- a/tools/testing/selftests/vm/userfaultfd.c
> +++ b/tools/testing/selftests/vm/userfaultfd.c
> @@ -66,6 +66,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
> 
>  #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;
> 
>   if (test_type != TEST_HUGETLB)
>   split_nr_pages = (nr_pages + 1) / 2;
>   else
>   split_nr_pages = nr_pages;
> 
> + if (signal_test) {
> + sigbuf = 
> + memset(, 0, sizeof(act));
> + act.sa_sigaction = sighndl;
> + act.sa_flags = SA_SIGINFO;
> + if (sigaction(SIGBUS, , 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) {
> + fprintf(stderr, "Signal repeated\n");
> + return 1;
> + }
> +
> + 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;
> +
>   if (test_type == TEST_HUGETLB)
>   return 0;
> 
> @@ -761,7 +817,7 @@ static int userfaultfd_events_test(void)
>   perror("fork"), exit(1);
> 
>   if (!pid)
> - return 

[RESEND PATCH v3 2/2] userfaultfd: selftest: Add tests for UFFD_FEATURE_SIGBUS feature

[Prakash Sangappa]

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 
---
Change log

v3:  Eliminated use of sig_repeat variable and simplified error return.

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..52740ae 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -66,6 +66,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #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;
 
if (test_type != TEST_HUGETLB)
split_nr_pages = (nr_pages + 1) / 2;
else
split_nr_pages = nr_pages;
 
+   if (signal_test) {
+   sigbuf = 
+   memset(, 0, sizeof(act));
+   act.sa_sigaction = sighndl;
+   act.sa_flags = SA_SIGINFO;
+   if (sigaction(SIGBUS, , 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) {
+   fprintf(stderr, "Signal repeated\n");
+   return 1;
+   }
+
+   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;
+
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, , 0);
if (err)
@@ -778,6 +834,70 @@ static int userfaultfd_events_test(void)
return userfaults != nr_pages;
 }
 
+static 

[RESEND PATCH v3 2/2] userfaultfd: selftest: Add tests for UFFD_FEATURE_SIGBUS feature

[Prakash Sangappa]

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 
---
Change log

v3:  Eliminated use of sig_repeat variable and simplified error return.

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..52740ae 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -66,6 +66,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #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;
 
if (test_type != TEST_HUGETLB)
split_nr_pages = (nr_pages + 1) / 2;
else
split_nr_pages = nr_pages;
 
+   if (signal_test) {
+   sigbuf = 
+   memset(, 0, sizeof(act));
+   act.sa_sigaction = sighndl;
+   act.sa_flags = SA_SIGINFO;
+   if (sigaction(SIGBUS, , 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) {
+   fprintf(stderr, "Signal repeated\n");
+   return 1;
+   }
+
+   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;
+
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, , 0);
if (err)
@@ -778,6 +834,70 @@ static int userfaultfd_events_test(void)
return userfaults != nr_pages;
 }
 
+static int