On s390/s390x backtrace(buffer, size) returns the series of called functions until
"makecontext_ret" and additional entries (up to "size") with "makecontext_ret".
GDB-backtrace is also warning:
"Backtrace stopped: previous frame identical to this frame (corrupt stack?)"
To reproduce this scenario you have to setup a new context with makecontext()
and activate it with setcontext(). See e.g. cf() function in testcase stdlib/tst-makecontext.c.
Or see bug in libgo "Bug 66303 - runtime.Caller() returns infinitely deep stack frames
on s390x " (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66303).
This patch omits the cfi_startproc/cfi_endproc directives in ENTRY/END macro of
__makecontext_ret. Thus no frame information is generated in .eh_frame and backtrace
stops after __makecontext_ret. There is also no .eh_frame info for _start or
thread_start functions.
ChangeLog:
[BZ #18508]
* stdlib/Makefile ($(objpfx)tst-makecontext3):
Depend on $(libdl).
* stdlib/tst-makecontext.c (cf): Test if _Unwind_Backtrace
is not called infinitely times.
(backtrace_helper): New function.
(trace_arg): New struct.
(st1): Enlarge stack size.
* sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S:
(__makecontext_ret): Omit cfi_startproc and cfi_endproc.
* sysdeps/unix/sysv/linux/s390/s390-64/__makecontext_ret.S:
Likewise.
(cf): Test sign extending the argument to long.
2008-04-10 Jakub Jelinek <jakub@redhat.com>
* stdlib/tst-makecontext.c (othervar): New variable.
(cf): Test sign extending the argument to long.
* sysdeps/powerpc/powerpc32/power5/fpu/s_isnanf.S: New file.
* sysdeps/powerpc/powerpc32/power6/fpu/s_isnan.S: New file.
* sysdeps/powerpc/powerpc32/power6/fpu/s_isnanf.S: New file.
* sysdeps/powerpc/powerpc64/power5/fpu/s_isnan.S: New file.
* sysdeps/powerpc/powerpc64/power6/fpu/s_isnan.S: New file.
* sysdeps/powerpc/powerpc64/power6x/fpu/s_isnan.S: New file.
2008-04-09 Ulrich Drepper <drepper@redhat.com>
* stdlib/tst-makecontext.c: Change parameter to cf to negative
value to check for correct sign extension.
[BZ #5436]
* sysdeps/unix/sysv/linux/x86_64/makecontext.c (__makecontext):
Copy 64-bit parameter values even though this is not required in
the standard.
* sysdeps/unix/sysv/linux/x86_64/vfork.S (__vfork): Record return
PC save.
