Problem with debugging -m32 program

[Mahmood Naderan via gcc-help]

I forgot to say that I am using gcc 6.4 and the command is

gcc -g -m32 -fno-stack-protector -z execstack -o mico mico.c



Regards,
Mahmood 

    On Monday, July 9, 2018, 12:02:10 PM GMT+4:30, Mahmood Naderan via gcc-help <gcc-help@gcc.gnu.org> wrote:  
 
  Hello,
I have compiled a simple c program with -m32 option. Thing is that when I want to copy some data into an array, it crashes 


Breakpoint 1, main (argc=1, argv=0xffffd154) at mico.c:35
35      strcpy( dest, buffer );
(gdb) p &buffer[0]
$1 = 0xffffcfb5 '\220' <repeats 50 times>, "\061\300Ph//shh/bin\211\343P\211\342S\211\341\260\v̀", '\220' <repeats 37 times>, "P\336\377\377\377\177"
(gdb) p &dest[0]
$2 = 0xffffd02c "\020\334\377", <incomplete sequence \367>
(gdb) x/100x 0xffffcfb5
0xffffcfb5:    0x90909090    0x90909090    0x90909090    0x90909090
0xffffcfc5:    0x90909090    0x90909090    0x90909090    0x90909090
0xffffcfd5:    0x90909090    0x90909090    0x90909090    0x90909090
0xffffcfe5:    0xc0319090    0x2f2f6850    0x2f686873    0x896e6962
0xffffcff5:    0xe28950e3    0xb0e18953    0x9080cd0b    0x90909090
0xffffd005:    0x90909090    0x90909090    0x90909090    0x90909090
0xffffd015:    0x90909090    0x90909090    0x90909090    0x90909090
0xffffd025:    0xffffde50    0x10007fff    0x00f7ffdc    0x5cf7ffca
0xffffd035:    0xe0ffffd1    0xb7000000    0xe0f7f047    0x90f7ffdd
0xffffd045:    0x00ffffd0    0x00000000    0x00000000    0x2c000000
(gdb) next

Program received signal SIGSEGV, Segmentation fault.
0x56555655 in main (argc=<error reading variable: Cannot access memory at address 0x90909090>, 
    argv=<error reading variable: Cannot access memory at address 0x90909094>) at mico.c:37
37    }




Without specifying -m32, there is no problem. I wonder why it tries to access 0x90909090. There is some problem with 32/64 bit data.


Regards,

Mahmood