x86/traps: Stop using ist_enter/exit() in do_int3()

		return;

	/*

	 * Use ist_enter despite the fact that we don't use an IST stack.

	 * We can be called from a kprobe in non-CONTEXT_KERNEL kernel

	 * mode or even during context tracking state changes.

	 * Unlike any other non-IST entry, we can be called from a kprobe in

	 * non-CONTEXT_KERNEL kernel mode or even during context tracking

	 * state changes.  Make sure that we wake up RCU even if we're coming

	 * from kernel code.

	 *

	 * This means that we can't schedule.  That's okay.

	 * This means that we can't schedule even if we came from a

	 * preemptible kernel context.  That's okay.

	 */

	ist_enter(regs);

	if (!user_mode(regs)) {

		rcu_nmi_enter();

		preempt_disable();

	}

	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");

#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP

	if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,

				SIGTRAP) == NOTIFY_STOP)

	cond_local_irq_disable(regs);

exit:

	ist_exit(regs);

	if (!user_mode(regs)) {

		preempt_enable_no_resched();

		rcu_nmi_exit();

	}

}

NOKPROBE_SYMBOL(do_int3);