diff mbox series

[v4,1/2] selftests/clone3: Fix broken test under !CONFIG_TIME_NS

Message ID 1685968410-5412-2-git-send-email-yangtiezhu@loongson.cn
State New
Headers
Series Modify code about clone timens |

Commit Message

Tiezhu Yang June 5, 2023, 12:33 p.m. UTC 
  When execute the following command to test clone3 on LoongArch:

  # cd tools/testing/selftests/clone3 && make && ./clone3

we can see the following error info:

  # [5719] Trying clone3() with flags 0x80 (size 0)
  # Invalid argument - Failed to create new process
  # [5719] clone3() with flags says: -22 expected 0
  not ok 18 [5719] Result (-22) is different than expected (0)

This is because if CONFIG_TIME_NS is not set, but the flag
CLONE_NEWTIME (0x80) is used to clone a time namespace, it
will return -EINVAL in copy_time_ns().

Here is the related code in include/linux/time_namespace.h:

  #ifdef CONFIG_TIME_NS
  ...
  struct time_namespace *copy_time_ns(unsigned long flags,
				      struct user_namespace *user_ns,
				      struct time_namespace *old_ns);
  ...
  #else
  ...
  static inline
  struct time_namespace *copy_time_ns(unsigned long flags,
				      struct user_namespace *user_ns,
				      struct time_namespace *old_ns)
  {
	  if (flags & CLONE_NEWTIME)
		  return ERR_PTR(-EINVAL);

	  return old_ns;
  }
  ...
  #endif

Here is the complete call stack:

  clone3()
    kernel_clone()
      copy_process()
        copy_namespaces()
          create_new_namespaces()
            copy_time_ns()
              clone_time_ns()

If kernel does not support CONFIG_TIME_NS, /proc/self/ns/time
will be not exist, and then we should skip clone3() test with
CLONE_NEWTIME.

With this patch under !CONFIG_TIME_NS:

  # cd tools/testing/selftests/clone3 && make && ./clone3
  ...
  # Time namespaces are not supported
  ok 18 # SKIP Skipping clone3() with CLONE_NEWTIME
  # Totals: pass:17 fail:0 xfail:0 xpass:0 skip:1 error:0

Fixes: 515bddf0ec41 ("selftests/clone3: test clone3 with CLONE_NEWTIME")
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 tools/testing/selftests/clone3/clone3.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

Thomas Gleixner June 6, 2023, 8:18 a.m. UTC | #1 
On Mon, Jun 05 2023 at 20:33, Tiezhu Yang wrote:
> When execute the following command to test clone3 on LoongArch:
>
>   # cd tools/testing/selftests/clone3 && make && ./clone3
>
> we can see the following error info:
>
>   # [5719] Trying clone3() with flags 0x80 (size 0)
>   # Invalid argument - Failed to create new process
>   # [5719] clone3() with flags says: -22 expected 0
>   not ok 18 [5719] Result (-22) is different than expected (0)
>
> This is because if CONFIG_TIME_NS is not set, but the flag
> CLONE_NEWTIME (0x80) is used to clone a time namespace, it
> will return -EINVAL in copy_time_ns().
>
> Here is the related code in include/linux/time_namespace.h:
>
>   #ifdef CONFIG_TIME_NS
>   ...
>   struct time_namespace *copy_time_ns(unsigned long flags,
> 				      struct user_namespace *user_ns,
> 				      struct time_namespace *old_ns);
>   ...
>   #else
>   ...
>   static inline
>   struct time_namespace *copy_time_ns(unsigned long flags,
> 				      struct user_namespace *user_ns,
> 				      struct time_namespace *old_ns)
>   {
> 	  if (flags & CLONE_NEWTIME)
> 		  return ERR_PTR(-EINVAL);
>
> 	  return old_ns;
>   }
>   ...
>   #endif

There is really no point in copying that code into the changelog. The
textual explanation that it returns -EINVAL is good enough.

> Here is the complete call stack:
>
>   clone3()
>     kernel_clone()
>       copy_process()
>         copy_namespaces()
>           create_new_namespaces()
>             copy_time_ns()
>               clone_time_ns()

Uninteresting too.

> If kernel does not support CONFIG_TIME_NS, /proc/self/ns/time
> will be not exist, and then we should skip clone3() test with
> CLONE_NEWTIME.

Correct.

> With this patch under !CONFIG_TIME_NS:
>
>   # cd tools/testing/selftests/clone3 && make && ./clone3
>   ...
>   # Time namespaces are not supported
>   ok 18 # SKIP Skipping clone3() with CLONE_NEWTIME
>   # Totals: pass:17 fail:0 xfail:0 xpass:0 skip:1 error:0

> Fixes: 515bddf0ec41 ("selftests/clone3: test clone3 with CLONE_NEWTIME")
> Suggested-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  tools/testing/selftests/clone3/clone3.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c
> index e495f89..c721f8a 100644
> --- a/tools/testing/selftests/clone3/clone3.c
> +++ b/tools/testing/selftests/clone3/clone3.c
> @@ -196,7 +196,12 @@ int main(int argc, char *argv[])
>  			CLONE3_ARGS_NO_TEST);
>  
>  	/* Do a clone3() in a new time namespace */
> -	test_clone3(CLONE_NEWTIME, 0, 0, CLONE3_ARGS_NO_TEST);
> +	if (access("/proc/self/ns/time", F_OK) == 0) {
> +		test_clone3(CLONE_NEWTIME, 0, 0, CLONE3_ARGS_NO_TEST);
> +	} else {
> +		ksft_print_msg("Time namespaces are not supported\n");
> +		ksft_test_result_skip("Skipping clone3() with CLONE_NEWTIME\n");
> +	}

Patch looks good otherwise.

Thanks,

        tglx
Tiezhu Yang June 6, 2023, 8:29 a.m. UTC | #2 
On 06/06/2023 04:18 PM, Thomas Gleixner wrote:
> On Mon, Jun 05 2023 at 20:33, Tiezhu Yang wrote:
>> When execute the following command to test clone3 on LoongArch:
>>
>>   # cd tools/testing/selftests/clone3 && make && ./clone3
>>
>> we can see the following error info:
>>
>>   # [5719] Trying clone3() with flags 0x80 (size 0)
>>   # Invalid argument - Failed to create new process
>>   # [5719] clone3() with flags says: -22 expected 0
>>   not ok 18 [5719] Result (-22) is different than expected (0)
>>
>> This is because if CONFIG_TIME_NS is not set, but the flag
>> CLONE_NEWTIME (0x80) is used to clone a time namespace, it
>> will return -EINVAL in copy_time_ns().
>>
>> Here is the related code in include/linux/time_namespace.h:
>>
>>   #ifdef CONFIG_TIME_NS
>>   ...
>>   struct time_namespace *copy_time_ns(unsigned long flags,
>> 				      struct user_namespace *user_ns,
>> 				      struct time_namespace *old_ns);
>>   ...
>>   #else
>>   ...
>>   static inline
>>   struct time_namespace *copy_time_ns(unsigned long flags,
>> 				      struct user_namespace *user_ns,
>> 				      struct time_namespace *old_ns)
>>   {
>> 	  if (flags & CLONE_NEWTIME)
>> 		  return ERR_PTR(-EINVAL);
>>
>> 	  return old_ns;
>>   }
>>   ...
>>   #endif
>
> There is really no point in copying that code into the changelog. The
> textual explanation that it returns -EINVAL is good enough.

OK, let me remove the code in the commit message.

>> Here is the complete call stack:
>>
>>   clone3()
>>     kernel_clone()
>>       copy_process()
>>         copy_namespaces()
>>           create_new_namespaces()
>>             copy_time_ns()
>>               clone_time_ns()
>
> Uninteresting too.

Will remove it too.

>
>> If kernel does not support CONFIG_TIME_NS, /proc/self/ns/time
>> will be not exist, and then we should skip clone3() test with
>> CLONE_NEWTIME.
>
> Correct.
>
>> With this patch under !CONFIG_TIME_NS:
>>
>>   # cd tools/testing/selftests/clone3 && make && ./clone3
>>   ...
>>   # Time namespaces are not supported
>>   ok 18 # SKIP Skipping clone3() with CLONE_NEWTIME
>>   # Totals: pass:17 fail:0 xfail:0 xpass:0 skip:1 error:0
>
>> Fixes: 515bddf0ec41 ("selftests/clone3: test clone3 with CLONE_NEWTIME")
>> Suggested-by: Thomas Gleixner <tglx@linutronix.de>
>> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
>> ---
>>  tools/testing/selftests/clone3/clone3.c | 7 ++++++-
>>  1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c
>> index e495f89..c721f8a 100644
>> --- a/tools/testing/selftests/clone3/clone3.c
>> +++ b/tools/testing/selftests/clone3/clone3.c
>> @@ -196,7 +196,12 @@ int main(int argc, char *argv[])
>>  			CLONE3_ARGS_NO_TEST);
>>
>>  	/* Do a clone3() in a new time namespace */
>> -	test_clone3(CLONE_NEWTIME, 0, 0, CLONE3_ARGS_NO_TEST);
>> +	if (access("/proc/self/ns/time", F_OK) == 0) {
>> +		test_clone3(CLONE_NEWTIME, 0, 0, CLONE3_ARGS_NO_TEST);
>> +	} else {
>> +		ksft_print_msg("Time namespaces are not supported\n");
>> +		ksft_test_result_skip("Skipping clone3() with CLONE_NEWTIME\n");
>> +	}
>
> Patch looks good otherwise.

Thank you, I will send v5 on Friday with updated commit message
if no more comments.

Thanks,
Tiezhu
diff mbox series

Patch

diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c
index e495f89..c721f8a 100644
--- a/tools/testing/selftests/clone3/clone3.c
+++ b/tools/testing/selftests/clone3/clone3.c
@@ -196,7 +196,12 @@  int main(int argc, char *argv[])
 			CLONE3_ARGS_NO_TEST);
 
 	/* Do a clone3() in a new time namespace */
-	test_clone3(CLONE_NEWTIME, 0, 0, CLONE3_ARGS_NO_TEST);
+	if (access("/proc/self/ns/time", F_OK) == 0) {
+		test_clone3(CLONE_NEWTIME, 0, 0, CLONE3_ARGS_NO_TEST);
+	} else {
+		ksft_print_msg("Time namespaces are not supported\n");
+		ksft_test_result_skip("Skipping clone3() with CLONE_NEWTIME\n");
+	}
 
 	ksft_finished();
 }