in kernel/signal.c [81:111]
asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
{
struct rt_sigframe __user *frame =
(struct rt_sigframe __user *)(regs->r1);
sigset_t set;
int rval;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
return rval;
badframe:
force_sig(SIGSEGV);
return 0;
}