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

[Stefan Liebler]

On 07/07/2017 03:53 PM, Stefan Liebler wrote:
> On 07/07/2017 12:45 PM, Florian Weimer wrote:
>> On 07/07/2017 12:22 PM, 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.
>>> +
>>> +     -If the kernel (<3.15) has no support for PTRACE_SINGLEBLOCK, the
>>> +     ptrace call has to fail with EIO. Then I continue the tracee with
>>> +     PTRACE_CONT.
>>> +
>>> +     -If the request 12 is interpreted as PTRACE_GETREGS, it will 
>>> fail too.
>>> +     It fails with EFAULT on intel / power as data argument is NULL.
>>> +     According to the man-page: "Unfortunately, under Linux, different
>>> +     variations of this fault will return EIO or EFAULT more or less
>>> +     arbitrarily".
>>> +     But if request 12 is interpreted as PTRACE_GETREGS, the first 
>>> ptrace
>>> +     call will touch the buffer which is detected by this test.  */
>>
>> I think the comment is still a bit off.  I think it is only necessary to
>> retain the second two lines, the other things is already implied by the
>> short comments in the code below.
> okay. I removed the other lines.
>>
>> (I have not tested whether this actually works.  I assume you have
>> checked a couple of userspace/kernel permutations.)
> Yes. I've run the test on several machines.
>>
>> Thanks,
>> Florian
>>
> 
> 
> If this is okay, I'll commit it on Monday.
Committed.
> 
> Bye.
> Stefan