[PATCH][BZ #18508] S390: Fix "backtrace() returns infinitely deep stack frames with makecontext()".

[H.J. Lu]

On Fri, Jul 3, 2015 at 2:11 AM, Florian Weimer <fweimer@redhat.com> wrote:
> On 06/15/2015 10:47 AM, Stefan Liebler wrote:
>> +/* We do not want .eh_frame info for __makecontext_ret to stop unwinding
>> +   if backtrace() was called within a context created by makecontext.
>> +   (there is also no .eh_frame info for _start or thread_start)  */
>
>> +/* We do not want .eh_frame info for __makecontext_ret to stop unwinding
>> +   if backtrace() was called within a context created by makecontext.
>> +   (there is also no .eh_frame info for _start or thread_start)  */
>
> I think this should read:
>
> “We do not want .eh_frame ifno so that __makecontext_ret stops unwinding
> if backtrace was called within a context created by makecontext.  (There
> is also no .eh_frame info for _start or thread_start.)”
>
> Could a native speaker review this, please?
>
> Rest of the patch seems okay to me.
>

The new test failed on Fedora/22/ i686:

cf (i=-78) at tst-makecontext.c:50
50 {
(gdb)
55  if (i != othervar || thr != 94)
(gdb)
51  struct trace_arg arg = { .size = 100, .cnt = -1 };
(gdb)
55  if (i != othervar || thr != 94)
(gdb)
66  handle = dlopen (LIBGCC_S_SO, RTLD_LAZY);
(gdb)
67  if (handle != NULL)
(gdb)
66  handle = dlopen (LIBGCC_S_SO, RTLD_LAZY);
(gdb)
67  if (handle != NULL)
(gdb)
69      unwind_backtrace = dlsym (handle, "_Unwind_Backtrace");
(gdb)
70      if (unwind_backtrace != NULL)
(gdb)
72  unwind_backtrace (backtrace_helper, &arg);
(gdb)

Program received signal SIGSEGV, Segmentation fault.
0xf7de14a1 in ?? () from /lib/libgcc_s.so.1

-- 
H.J.