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

[Stefan Liebler]

On 06/13/2017 10:05 PM, Dmitry V. Levin wrote:
> On Tue, Jun 06, 2017 at 12:17:33PM +0200, Stefan Liebler wrote:
> [...]
>> diff --git a/sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c b/sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c
>> new file mode 100644
 >> [...]
>> +      /* Get information about tracee: gprs, last breaking address.  */
>> +      parea.len = sizeof (regs);
>> +      parea.process_addr = (unsigned long) ®s;
>> +      parea.kernel_addr = 0;
>> +      ptrace (PTRACE_PEEKUSR_AREA, pid, &parea);
> 
> Note that you can verify whether PTRACE_PEEKUSR_AREA has returned
> the expected result by comparing registers with those returned
> by PTRACE_GETREGSET.  The latter is implemented on s390 since
> linux 2.6.27 so its use in glibc is safe.
> 
Okay. Now the gprs are obtained by PTRACE_PEEKUSR_AREA and 
PTRACE_GETREGSET. Afterwards I use memcmp to check whether the values 
are the same.
>> +      ptrace (PTRACE_GET_LAST_BREAK, pid, NULL, &last_break);
> 
> As these ptrace calls are expected to succeed,
> you might want to check their return code.
> 
Done with several usages of TEST_VERIFY_EXIT.

>> +
>> +      printf ("child IA: %p last_break: %p\n",
>> +	      (void *) regs[1], (void *) last_break);
>> +
>> +      /* Execute tracee until next taken branch.
>> +
>> +	 Note:
>> +	 Before the commit which introduced this testcase,
>> +	 <glibc>/sysdeps/unix/sysv/linux/s390/sys/ptrace.h
>> +	 uses ptrace-request 12 for PTRACE_GETREGS,
>> +	 but <kernel>/include/uapi/linux/ptrace.h
>> +	 uses 12 for PTRACE_SINGLEBLOCK.
>> +
>> +	 The s390 kernel has no support for PTRACE_GETREGS!
>> +	 Thus glibc ptrace.h is adjusted to match kernel ptrace.h.
>> +
>> +	 This test ensures, that PTRACE_SINGLEBLOCK defined in glibc
>> +	 works as expected.  If the kernel would interpret it as
>> +	 PTRACE_GETREGS, then the tracee will not make any progress
>> +	 and this testcase will time out.  */
>> +      ptrace (req_singleblock, pid, NULL, NULL);
> 
> Likewise.
> 
> 


I've attached the patch with the mentioned changes and the NEWS entry 
requested by Andreas.

Is this okay?

Bye
Stefan
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