[PATCH] S390: Sync ptrace.h with kernel. [BZ #21539]

[Stefan Liebler]

On 07/04/2017 05:37 PM, Stefan Liebler wrote:
> On 07/04/2017 11:41 AM, Florian Weimer wrote:
>> On 07/04/2017 10:22 AM, Stefan Liebler wrote:
>>> +      /* Ptrace request 12 is done with zero data argument:
>>> +     -If the kernel has support for PTRACE_SINGLEBLOCK (then the kernel
>>> +     header asm/ptrace.h defines this macro), the ptrace call is not 
>>> allowed
>>> +     to fail and has to continue the tracee until next taken branch.
>>
>> I think this is still bogus.  We can compile with newer kernel headers
>> than the host kernel, and this will cause the test to fail.
>>
>> Thanks,
>> Florian
>>
> 
> Okay.
> So I can check the return value of the second ptrace (req_singleblock, 
> pid, NULL, NULL) call at runtime to determine the kernel-support:
> 
>        errno = 0;
>        ret = ptrace (req_singleblock, pid, NULL, NULL);
>        if (ret == 0)
>      {
>        /* The kernel has support for PTRACE_SINGLEBLOCK ptrace request. */
>        TEST_VERIFY_EXIT (errno == 0);
>      }
>        else
>      {
>        /* The kernel (< 3.15) has no support for PTRACE_SINGLEBLOCK ptrace
>           request. */
>        TEST_VERIFY_EXIT (errno == EIO);
>        TEST_VERIFY_EXIT (ret == -1);
> 
>        /* Just continue tracee until it exits normally.  */
>        TEST_VERIFY_EXIT (ptrace (PTRACE_CONT, pid, NULL, NULL) == 0);
>      }
> 
> 
> 
> Then the test runs on kernels with / without support for 
> PTRACE_SINGLEBLOCK. The first ptrace call ensures that request 12 is not 
> interpreted as PTRACE_GETREGS.
> 
> Bye.
> Stefan
> 

Here is the complete patch with the change mentioned above.
Is this approach okay?

Bye.
Stefan
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