report a segment fault bug of systemtap

[maliubiao <maliubiao at gmail dot com>]

SCRIPT :

global c = 0;
probe process("/data/project/c/nginx-build/sbin/nginx").function("ngx_worker_process_cycle")
{
    if (c < 1) {
        printf("%s\n", user_string($cycle->hostname->data))
        c += 1
    }
}

probe process("/data/project/c/nginx-build/sbin/nginx").function("ngx_epoll_process_events*")
{
    /* iter over array ngx_modules */
    for (i=0; i < 512; i++) {
        index = @var("ngx_modules@ngx_modules.c")[i]->index
        if (index != i) {
            break
        }
        ngx_modules = @var("ngx_modules@ngx_modules.c")[i]
        ctx = @cast(ngx_modules, "ngx_module_s")->ctx
        name = @cast(ctx, "ngx_core_module_t")->name->data
        if (name) {
            printf("index: %s\n", i, user_string(name));
        }
    }
}

STACK TRACE:

Pass 1: parsed user script and 100 library script(s) using
89752virt/29968res/2480shr/28316data kb, in 150usr/10sys/26180real ms.

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff777e946 in __strcmp_sse42 () from /lib64/libc.so.6
(gdb) bt
#0  0x00007ffff777e946 in __strcmp_sse42 () from /lib64/libc.so.6
#1  0x00000000004d57ad in dwarf_atvar_query::atvar_query_cu (cudie=0x24028a0,
    data=0x7fffffffba80) at tapsets.cxx:4192
#2  0x000000000054a862 in dwflpp::iterate_over_cus (this=<optimized out>,
    callback=0x4d5760 <dwarf_atvar_query::atvar_query_cu(Dwarf_Die*, void*)>,
    data=0x7fffffffba80, want_types=false) at dwflpp.cxx:466
#3  0x00000000004b48cd in query_module (mod=<optimized out>,
    name=<optimized out>, addr=4194304, arg=0x7fffffffba80) at tapsets.cxx:2132
#4  0x00007ffff71edfa2 in dwfl_getmodules (dwfl=0x228cd60,
    callback=0x4b4770 <query_module(Dwfl_Module*, void**, char const*,
Dwarf_Addr, void*)>, arg=0x7fffffffba80, offset=0)
    at ../.././elfutils-0.157/libdwfl/dwfl_getmodules.c:82
#5  0x00000000004ca254 in dwarf_atvar_expanding_visitor::visit_atvar_op (
    this=0x2284b40, e=0x23c4030) at tapsets.cxx:4296
#6  0x0000000000453fb3 in update_visitor::require<expression> (this=0x2284b40,
    src=<optimized out>, clearok=false) at staptree.h:970
#7  0x00000000004c8e2b in replace<expression> (clearok=false,
    src=@0x23c3d88: 0x23c4030, this=0x2284b40) at staptree.h:992
#8  var_expanding_visitor::rewrite_lvalue (this=this@entry=0x2284b40,
    tok=0x21eeaf0, eop="=", lvalue=@0x23c3d78: 0x23c3da0,
    rvalue=@0x23c3d88: 0x23c4030) at tapsets.cxx:2354
#9  0x00000000004c9369 in var_expanding_visitor::visit_assignment (
    this=0x2284b40, e=0x23c3d60) at tapsets.cxx:2400
---Type <return> to continue, or q <return> to quit---
#10 0x000000000044e1df in assignment::visit (this=0x23c3d60, u=0x2284b40)
    at staptree.cxx:1469
#11 0x0000000000453fb3 in update_visitor::require<expression> (this=0x2284b40,
    src=<optimized out>, clearok=false) at staptree.h:970
#12 0x000000000044c587 in replace<expression> (clearok=false,
    src=<optimized out>, this=0x2284b40) at staptree.h:992
#13 update_visitor::visit_expr_statement (this=0x2284b40, s=0x23c3d40)
    at staptree.cxx:2599
#14 0x000000000044a5bf in require<statement> (clearok=false,
    src=<optimized out>, this=0x2284b40) at staptree.h:970
#15 replace<statement> (clearok=false, src=@0x23c3d00: 0x23c3d40,
    this=0x2284b40) at staptree.h:992
#16 update_visitor::visit_block (this=0x2284b40, s=0x23c3cd0)
    at staptree.cxx:2571
#17 0x0000000000453af3 in update_visitor::require<statement> (this=0x2284b40,
    src=<optimized out>, clearok=false) at staptree.h:970
#18 0x000000000044cd8d in replace<statement> (clearok=false,
    src=@0x23c37b8: 0x23c3cd0, this=0x2284b40) at staptree.h:992
#19 update_visitor::visit_for_loop (this=0x2284b40, s=0x23c3790)
    at staptree.cxx:2618
#20 0x000000000044a5bf in require<statement> (clearok=false,
    src=<optimized out>, this=0x2284b40) at staptree.h:970
#21 replace<statement> (clearok=false, src=@0x23c3ab0: 0x23c3790,
---Type <return> to continue, or q <return> to quit---
    this=0x2284b40) at staptree.h:992
#22 update_visitor::visit_block (this=0x2284b40, s=0x23c3be0)
    at staptree.cxx:2571
#23 0x000000000045fba3 in require<statement> (clearok=false,
    src=<optimized out>, this=0x2284b40) at staptree.h:970
#24 replace<statement> (clearok=false, src=@0x23c3870: 0x23c3be0,
    this=0x2284b40) at staptree.h:992
#25 semantic_pass_symbols (s=...) at elaborate.cxx:1643
#26 0x000000000046c71c in semantic_pass (s=...) at elaborate.cxx:1985
#27 0x0000000000413c10 in passes_0_4 (s=...) at main.cxx:744
#28 0x000000000040c97b in main (argc=<optimized out>, argv=<optimized out>)
    at main.cxx:1101

ENV:
stap --version
Systemtap translator/driver (version 2.4/0.157, commit
release-2.3-131-g1acfc03 + changes)
uname -a
Linux linux-6pwq.site 3.11.1-1.16-desktop+ #2 SMP PREEMPT Sun Oct 6
11:07:07 CST 2013 x86_64 x86_64 x86_64 GNU/Linux

any idea ?