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

["Dmitry V. Levin" <ldv at altlinux dot org>]

On Mon, Jun 19, 2017 at 03:10:57PM +0200, Stefan Liebler wrote:
> 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) &regs;
> >> +      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?

Looks fine, thanks.


-- 
ldv

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