I'm trying to debug a seg fault in C in a research code. I cannot modify the source code/makefile. Since I can't modify the makefile (i.e., recompile the program) and the executable was not compiled with the -g option, I assume that throws gdb debugging out the window? Or is there a way to use gdb without compiling the executable using -g?

I could request to make changes to the source code, but I am almost certain the seg fault is due to one of my input files, so it shouldn't be a source code problem. 

Someone had suggested I use "strace," which I am not very familiar with. Here is the end of the output when I strace'd my program:

```
close(27)                               = 0
munmap(0x2abe4843d000, 65536)           = 0
write(2, "==== backtrace ====\n", 20==== backtrace ====
)   = 20
write(2, " 2 0x00000000000597bc mxm_handle"..., 113 2 0x00000000000597bc mxm_handle_error()  /var/tmp/OFED_topdir/BUILD/mxm-3.3.3055/src/mxm/util/debug/debug.c:641
) = 113
write(2, " 3 0x000000000005992c mxm_error_"..., 121 3 0x000000000005992c mxm_error_signal_handler()  /var/tmp/OFED_topdir/BUILD/mxm-3.3.3055/src/mxm/util/debug/debug.c:616
) = 121
write(2, " 4 0x00000037ccc326a0 killpg()  "..., 37 4 0x00000037ccc326a0 killpg()  ??:0
) = 37
write(2, " 5 0x00000000004ec6ef interpLema"..., 99 5 0x00000000004ec6ef interpLemansToMopar_linear()  /home/dzdang/w16/sources/mopar_bc_interp.c:559
) = 99
write(2, " 6 0x000000000040c4ee main()  /h"..., 68 6 0x000000000040c4ee main()  /home/dzdang/w16/sources/lemans.c:611
) = 68
write(2, " 7 0x00000037ccc1ed5d __libc_sta"..., 48 7 0x00000037ccc1ed5d __libc_start_main()  ??:0
) = 48
write(2, " 8 0x0000000000403c99 _start()  "..., 37 8 0x0000000000403c99 _start()  ??:0
) = 37
write(2, "===================\n", 20===================
)   = 20
brk(0x2958000)                          = 0x2958000
tgkill(15432, 15432, SIGSEGV)           = 0
rt_sigreturn(0x3c48)                    = 46993935941696
--- SIGSEGV (Segmentation fault) @ 0 (0) ---
+++ killed by SIGSEGV +++
Segmentation fault

```

Any ideas what this means? Or any suggestions on how to debug?