2009/7/2 Ian Lance Taylor <iant@xxxxxxxxxx>:
> The intention is that if the stack is not mapped, the store will trigger
> a fault--an access to an invalid memory address. Based on the address,
> the OS will recognize that this access is to the stack, and will
> automatically increase the stack size. Or, if that is not possible, the
> OS will halt the program.
>
> I suspect that -fstack-check does not do what you think it does. It
> doesn't check that you are using the stack correctly. It checks that
> you do not run past the end of the stack. This avoids a certain class
> of errors which can arise when using functions with very large stack
> frames in a multi-threaded program: such functions can accidentally skip
> into the stack frame of a different thread.
>
> Ian
>
$cat stack_check.c
-------------------------------
void foo()
{
char buf[8];
int a = rand();
buf[0] = 0;
buf[1] = 1;
buf[2] = 2;
buf[3] = 3;
buf[4] = 4;
buf[5] = 5;
buf[6] = 6;
buf[7] = 7;
buf[8] = 8;
}
int main(int argc, char *argv[])
{
srand(time(NULL));
foo();
return 0;
}
-------------------------------
$gcc -fstack-check stack_check.c
$./a.exe
9 [main] a 2796 _cygtls::handle_exceptions: Error while dumping
state (probably corrupted stack)
Segmentation fault (core dumped)
On i386 arch, gcc is smart enough to check if the stack is corrupted.
I wonder if there is some way to do this on MIPS.
PRC
Jul 2,2009
