Run stap -e 'probe kernel.function("sys_open") {}'
with kernel-debuginfo installed, but without the same kernel RPM.
stap will segv within dwfl_end.  A way to simulate it is just to
rename the /lib/modules/`uname -r` directory briefly.

The lowest-level problem is that dwfl->nmodules == 1 even as
dwfl->modules==NULL.


Pass 1: parsed user script and 38 library script(s) in 340usr/10sys/360real ms.
semantic error: libdwfl failure (missing kernel 2.6.18-53.1.13.el5 ppc64
debuginfo): No such file or directory while resolving probe point
kernel.function("sys_open")

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 552390915504 (LWP 1659)]
0x000004000001b814 in dwfl_end (dwfl=0x109df520)
    at elfutils-0.131/libdwfl/dwfl_end.c:58
58      elfutils-0.131/libdwfl/dwfl_end.c: No such file or directory.
        in elfutils-0.131/libdwfl/dwfl_end.c
Current language:  auto; currently c
(gdb) bt
#0  0x000004000001b814 in dwfl_end (dwfl=0x109df520)
    at elfutils-0.131/libdwfl/dwfl_end.c:58
#1  0x00000000100b1f44 in ~dwflpp (this=0x109df790) at tapsets.cxx:1995
#2  0x00000000100b23ac in dwarf_builder::build_no_more (this=0x109de040, 
    s=@0xfffff8ce618) at tapsets.cxx:2308
#3  0x000000001003f894 in match_node::build_no_more (this=0x109de460, 
    s=@0xfffff8ce618) at elaborate.cxx:427
#4  0x000000001003f84c in match_node::build_no_more (this=0x109de360, 
    s=@0xfffff8ce618) at elaborate.cxx:426
#5  0x000000001003f84c in match_node::build_no_more (this=0x109de060, 
    s=@0xfffff8ce618) at elaborate.cxx:426
#6  0x000000001003f84c in match_node::build_no_more (this=0x10120240, 
    s=@0xfffff8ce618) at elaborate.cxx:426
#7  0x00000000100499a8 in semantic_pass_symbols (s=@0xfffff8ce618)
    at elaborate.cxx:1155
#8  0x000000001004e450 in semantic_pass (s=@0xfffff8ce618)
    at elaborate.cxx:1172
#9  0x000000001000c1cc in main (argc=-7541744, argv=<value optimized out>)
    at main.cxx:719
#10 0x000000809d159700 in generic_start_main (
    main=@0x10116668: 0x10009950 <main>, argc=0, ubp_av=0xfffff8cf878, 
    auxvec=0xfffff8cf9a8, init=<value optimized out>, fini=dwarf2_read_address:
Corrupted DWARF expression.
)
    at ../csu/libc-start.c:231
#11 0x000000809d159980 in __libc_start_main (argc=5, ubp_av=0xfffff8cf878, 
    ubp_ev=<value optimized out>, auxvec=0xfffff8cf9a8, 
    rtld_fini=@0x809d100370: 0x809d0da390 <_dl_fini>, stinfo=0x1010c978, 
    stack_on_entry=0xfffff8cf7f0)
    at ../sysdeps/unix/sysv/linux/powerpc/libc-start.c:127
#12 0x0000000000000000 in ?? ()
(gdb) frame 0
#0  0x000004000001b814 in dwfl_end (dwfl=0x109df520)
    at elfutils-0.131/libdwfl/dwfl_end.c:58
58      in elfutils-0.131/libdwfl/dwfl_end.c
(gdb) p dwfl
$1 = (Dwfl *) 0x109df520
(gdb) p *dwfl
$2 = {callbacks = 0x10110bb8, modulelist = 0x109df8a0, modules = 0x0, 
  nmodules = 1, offline_next_address = 65536}
(gdb) p *dwfl->modulelist
$3 = {dwfl = 0x109df520, next = 0x0, userdata = 0x0, 
  name = 0x109df9c0 "kernel", low_addr = 13835058055282163712, 
  high_addr = 13835058055289238672, build_id_bits = 0x0, build_id_vaddr = 0, 
  build_id_len = 0, main = {
    name = 0x109df9e0 "/usr/lib/debug/lib/modules/2.6.18-53.1.13.el5/vmlinux", 
    fd = 6, valid = false, relocated = false, elf = 0x109dfa60, bias = 0}, 
  debug = {name = 0x0, fd = 0, valid = false, relocated = false, elf = 0x0, 
    bias = 0}, ebl = 0x0, e_type = 3, elferr = DWFL_E_NOERROR, 
  reloc_info = 0x0, symfile = 0x0, symdata = 0x0, syments = 0, 
  symstrdata = 0x0, symxndxdata = 0x0, symerr = DWFL_E_NOERROR, dw = 0x0, 
  dwerr = DWFL_E_NOERROR, first_cu = 0x0, cu = 0x0, ncu = 0, 
  lazy_cu_root = 0x0, lazycu = 0, aranges = 0x0, naranges = 0, gc = false}
(gdb) p i
$4 = 0
(gdb) p *dwfl->modules
Cannot access memory at address 0x0
(gdb) p *dwfl
$6 = {callbacks = 0x10110bb8, modulelist = 0x109df8a0, modules = 0x0, 
  nmodules = 1, offline_next_address = 65536}
(gdb) p dwfl->nmodules
$7 = 1