/*
* start the push here
*/
static void stress_stackmmap_push_start(void)
{
/* stack for SEGV handler must not be on the stack */
static uint8_t stack_sig[SIGSTKSZ + STACK_ALIGNMENT];
struct sigaction new_action;
/*
* We need to handle SEGV signals when we
* hit the end of the mmap'd stack; however
* an alternative signal handling stack
* is required because we ran out of stack
*/
(void)memset(&new_action, 0, sizeof new_action);
new_action.sa_handler = stress_segvhandler;
(void)sigemptyset(&new_action.sa_mask);
new_action.sa_flags = SA_ONSTACK;
if (sigaction(SIGSEGV, &new_action, NULL) < 0)
return;
/*
* We need an alternative signal stack
* to handle segfaults on an overrun
* mmap'd stack
*/
(void)memset(stack_sig, 0, sizeof(stack_sig));
if (stress_sigaltstack(stack_sig, SIGSTKSZ) < 0)
return;
stress_stackmmap_push_msync();
}
/*
* push values onto file backed mmap'd stack and
* force msync on the map'd region if page boundary
* has changed
*/
static void stress_stackmmap_push_msync(void)
{
void *addr = (void *)(((uintptr_t)&addr) & page_mask);
static void *laddr;
if (addr != laddr) {
msync(addr, page_size, mwc8() >= 128 ? MS_SYNC : MS_ASYNC);
laddr = addr;
}
if (opt_do_run)
stress_stackmmap_push_msync();
}
/*
* push values onto file backed mmap'd stack and
* force msync on the map'd region if page boundary
* has changed
*/
static void stress_stackmmap_push_msync(void)
{
void *addr = (void *)(((uintptr_t)&addr) & page_mask);
static void *laddr;
char waste[64];
waste[0] = 0;
waste[sizeof(waste) - 1] = 0;
if (addr != laddr) {
(void)shim_msync(addr, page_size,
(mwc8() & 1) ? MS_ASYNC : MS_SYNC);
laddr = addr;
}
if (g_keep_stressing_flag)
stress_stackmmap_push_msync();
}
