[1/3] userfaultfd: selftest: Fix checking of userfaultfd_open() result
diff mbox series

Message ID 20180725024209.32586-2-bauerman@linux.ibm.com
State New
Headers show
Series
  • userfaultfd: selftest: Improve behavior with older kernels
Related show

Commit Message

Thiago Jung Bauermann July 25, 2018, 2:42 a.m. UTC
If the userfaultfd test is run on a kernel with CONFIG_USERFAULTFD=n, it
will report that the system call is not available yet go ahead and continue
anyway:

  # ./userfaultfd anon 30 1
  nr_pages: 480, nr_pages_per_cpu: 120
  userfaultfd syscall not available in this kernel
  bounces: 0, mode:, register failure

This is because userfaultfd_open() returns 0 on success and 1 on error but
all callers assume that it returns < 0 on error.

Since the convention of the test as a whole is the one used by
userfault_open(), fix its callers instead. Now the test behaves correctly:

  # ./userfaultfd anon 30 1
  nr_pages: 480, nr_pages_per_cpu: 120
  userfaultfd syscall not available in this kernel

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 tools/testing/selftests/vm/userfaultfd.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)


--
To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Comments

Mike Rapoport July 25, 2018, 1:59 p.m. UTC | #1
Hi,

On Tue, Jul 24, 2018 at 11:42:07PM -0300, Thiago Jung Bauermann wrote:
> If the userfaultfd test is run on a kernel with CONFIG_USERFAULTFD=n, it
> will report that the system call is not available yet go ahead and continue
> anyway:
> 
>   # ./userfaultfd anon 30 1
>   nr_pages: 480, nr_pages_per_cpu: 120
>   userfaultfd syscall not available in this kernel
>   bounces: 0, mode:, register failure
> 
> This is because userfaultfd_open() returns 0 on success and 1 on error but
> all callers assume that it returns < 0 on error.
> 
> Since the convention of the test as a whole is the one used by
> userfault_open(), fix its callers instead. Now the test behaves correctly:
> 
>   # ./userfaultfd anon 30 1
>   nr_pages: 480, nr_pages_per_cpu: 120
>   userfaultfd syscall not available in this kernel
> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

It seems that this patch is superseded by the second patch in this series.

> ---
>  tools/testing/selftests/vm/userfaultfd.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
> index 7b8171e3128a..e4099afe7557 100644
> --- a/tools/testing/selftests/vm/userfaultfd.c
> +++ b/tools/testing/selftests/vm/userfaultfd.c
> @@ -859,7 +859,7 @@ static int userfaultfd_zeropage_test(void)
>  	if (uffd_test_ops->release_pages(area_dst))
>  		return 1;
> 
> -	if (userfaultfd_open(0) < 0)
> +	if (userfaultfd_open(0))
>  		return 1;
>  	uffdio_register.range.start = (unsigned long) area_dst;
>  	uffdio_register.range.len = nr_pages * page_size;
> @@ -902,7 +902,7 @@ static int userfaultfd_events_test(void)
> 
>  	features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
>  		UFFD_FEATURE_EVENT_REMOVE;
> -	if (userfaultfd_open(features) < 0)
> +	if (userfaultfd_open(features))
>  		return 1;
>  	fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
> 
> @@ -961,7 +961,7 @@ static int userfaultfd_sig_test(void)
>  		return 1;
> 
>  	features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
> -	if (userfaultfd_open(features) < 0)
> +	if (userfaultfd_open(features))
>  		return 1;
>  	fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
> 
> @@ -1027,7 +1027,7 @@ static int userfaultfd_stress(void)
>  	if (!area_dst)
>  		return 1;
> 
> -	if (userfaultfd_open(0) < 0)
> +	if (userfaultfd_open(0))
>  		return 1;
> 
>  	count_verify = malloc(nr_pages * sizeof(unsigned long long));
Thiago Jung Bauermann July 30, 2018, 11:53 p.m. UTC | #2
Hello Mike,

Thanks for promptly reviewing the patches.

Mike Rapoport <rppt@linux.vnet.ibm.com> writes:

> Hi,
>
> On Tue, Jul 24, 2018 at 11:42:07PM -0300, Thiago Jung Bauermann wrote:
>> If the userfaultfd test is run on a kernel with CONFIG_USERFAULTFD=n, it
>> will report that the system call is not available yet go ahead and continue
>> anyway:
>>
>>   # ./userfaultfd anon 30 1
>>   nr_pages: 480, nr_pages_per_cpu: 120
>>   userfaultfd syscall not available in this kernel
>>   bounces: 0, mode:, register failure
>>
>> This is because userfaultfd_open() returns 0 on success and 1 on error but
>> all callers assume that it returns < 0 on error.
>>
>> Since the convention of the test as a whole is the one used by
>> userfault_open(), fix its callers instead. Now the test behaves correctly:
>>
>>   # ./userfaultfd anon 30 1
>>   nr_pages: 480, nr_pages_per_cpu: 120
>>   userfaultfd syscall not available in this kernel
>>
>> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
>
> It seems that this patch is superseded by the second patch in this series.

Yes, but since this is a simple bugfix while the other patch is a
proposed improvement which can be debated, I think it's worthwhile to
keep them separate.

--
Thiago Jung Bauermann
IBM Linux Technology Center

--
To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch
diff mbox series

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 7b8171e3128a..e4099afe7557 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -859,7 +859,7 @@  static int userfaultfd_zeropage_test(void)
 	if (uffd_test_ops->release_pages(area_dst))
 		return 1;
 
-	if (userfaultfd_open(0) < 0)
+	if (userfaultfd_open(0))
 		return 1;
 	uffdio_register.range.start = (unsigned long) area_dst;
 	uffdio_register.range.len = nr_pages * page_size;
@@ -902,7 +902,7 @@  static int userfaultfd_events_test(void)
 
 	features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
 		UFFD_FEATURE_EVENT_REMOVE;
-	if (userfaultfd_open(features) < 0)
+	if (userfaultfd_open(features))
 		return 1;
 	fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
 
@@ -961,7 +961,7 @@  static int userfaultfd_sig_test(void)
 		return 1;
 
 	features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
-	if (userfaultfd_open(features) < 0)
+	if (userfaultfd_open(features))
 		return 1;
 	fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
 
@@ -1027,7 +1027,7 @@  static int userfaultfd_stress(void)
 	if (!area_dst)
 		return 1;
 
-	if (userfaultfd_open(0) < 0)
+	if (userfaultfd_open(0))
 		return 1;
 
 	count_verify = malloc(nr_pages * sizeof(unsigned long long));