On 2012-10-24 12:34, Volodymyr Kostyrko wrote:
...
Can you attempt to figure out what the illegal instruction was, in that
case?
How can I do that? I'm not very familiar with gdb.
Try the following:
$ gdb /path/to/crashed-program /path/to/crashed-program.core
GNU gdb (GDB) 7.5 [GDB v7.5 for FreeBSD]
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "i386-portbld-freebsd10.0".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /path/to/crashed-program...(no debugging symbols
found)...done.
[New process 100137]
Core was generated by `crashed-program'.
Program terminated with signal 4, Illegal instruction.
#0 0x08048632 in main ()
(gdb) disassemble
Dump of assembler code for function main:
0x08048600 <+0>: push %ebp
0x08048601 <+1>: mov %esp,%ebp
0x08048603 <+3>: sub $0x18,%esp
0x08048606 <+6>: lea 0x80486b0,%eax
0x0804860c <+12>: movl $0x0,-0x4(%ebp)
0x08048613 <+19>: mov %eax,(%esp)
0x08048616 <+22>: call 0x8048390 <printf@plt>
0x0804861b <+27>: mov 0x8049868,%ecx
0x08048621 <+33>: mov %ecx,(%esp)
0x08048624 <+36>: mov %eax,-0x8(%ebp)
0x08048627 <+39>: call 0x80483c0 <fflush@plt>
0x0804862c <+44>: lea 0x80486ce,%ecx
=> 0x08048632 <+50>: (bad)
0x08048633 <+51>: (bad)
0x08048634 <+52>: (bad)
0x08048635 <+53>: (bad)
0x08048636 <+54>: (bad)
0x08048637 <+55>: (bad)
0x08048638 <+56>: (bad)
0x08048639 <+57>: decl 0x4589240c(%ecx)
0x0804863f <+63>: hlt
0x08048640 <+64>: call 0x8048390 <printf@plt>
0x08048645 <+69>: mov 0x8049868,%ecx
0x0804864b <+75>: mov %ecx,(%esp)
0x0804864e <+78>: mov %eax,-0x10(%ebp)
0x08048651 <+81>: call 0x80483c0 <fflush@plt>
0x08048656 <+86>: mov $0x0,%ecx
0x0804865b <+91>: mov %eax,-0x14(%ebp)
0x0804865e <+94>: mov %ecx,%eax
0x08048660 <+96>: add $0x18,%esp
0x08048663 <+99>: pop %ebp
0x08048664 <+100>: ret
End of assembler dump.
(gdb) info registers
eax 0x0 0
ecx 0x80486ce 134514382
edx 0x2819a8d4 672770260
ebx 0xbfbfd650 -1077946800
esp 0xbfbfd5e0 0xbfbfd5e0
ebp 0xbfbfd5f8 0xbfbfd5f8
esi 0xbfbfd64c -1077946804
edi 0x0 0
eip 0x8048632 0x8048632 <main+50>
eflags 0x10286 [ PF SF IF RF ]
cs 0x33 51
ss 0x3b 59
ds 0x3b 59
es 0x3b 59
fs 0x3b 59
gs 0x1b 27
It should highlight the illegal instruction with the => arrow. Just
copy/paste the whole piece of assembly, and the registers info.
...
On the problematic athlons, can you please post the exact CPUIDs from
dmesg? If you have WITH_CLANG_EXTRAS enabled, please also post the
output of "opt -version".
Oct 24 01:47:20 limbo kernel: CPU: AMD Athlon(tm) XP 2500+ (1833.95-MHz
686-class CPU)
Oct 24 01:47:20 limbo kernel: Origin = "AuthenticAMD" Id = 0x6a0
Family = 0x6 Model = 0xa Stepping = 0
Ok, this CPU should be recognized by llvm as "athlon-xp". There is in
fact no need to compile all the WITH_CLANG_EXTRAS programs, I just
remembered.
If you compile a sample program with -march=native -v, it should show
you the detected CPU in the verbose command line output, e.g.:
$ clang -v -march=native -c /home/dim/src/example.c
FreeBSD clang version 3.2 (trunk 162107) 20120817
Target: i386-unknown-freebsd10.0
Thread model: posix
"/usr/bin/clang" -cc1 -triple i386-unknown-freebsd10.0 -emit-obj -mrelax-all
-disable-free -main-file-name example.c -mrelocation-model static -mdisable-fp-elim
-masm-verbose -mconstructor-aliases -target-cpu core2 -momit-leaf-frame-pointer -v
-coverage-file hw.o -resource-dir /usr/bin/../lib/clang/3.2 -fmodule-cache-path
/home/dim/tmp/clang-module-cache -fdebug-compilation-dir /home/dim/src -ferror-limit 19
-fmessage-length 265 -mstackrealign -fobjc-runtime=gnustep -fdiagnostics-show-option
-fcolor-diagnostics -o hw.o -x c /home/dim/src/example.c
clang -cc1 version 3.2 based upon LLVM 3.2svn default target
i386-unknown-freebsd10.0
ignoring nonexistent directory "/usr/bin/../lib/clang/3.2/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/clang/3.2
/usr/include
End of search list.
In my case, it uses "-target-cpu core2", as you can see.
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