Commit 4b57dccc authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'core-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull irqpoll update from Thomas Gleixner:
 "A single update for irqpoll:

  Ensure that a raised soft interrupt is handled after pulling the
  blk_cpu_iopoll backlog from a unplugged CPU. This prevents that the
  CPU which runs that code reaches idle with soft interrupts pending"

* tag 'core-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  lib/irq_poll: Prevent softirq pending leak in irq_poll_cpu_dead()
parents 140e40e3 75d8cce1

lib/irq_poll.c

+6 −2
Original line number Diff line number Diff line
@@ -188,14 +188,18 @@ EXPORT_SYMBOL(irq_poll_init); 
static int irq_poll_cpu_dead(unsigned int cpu)

{

	/*

	 * If a CPU goes away, splice its entries to the current CPU

	 * and trigger a run of the softirq

	 * If a CPU goes away, splice its entries to the current CPU and

	 * set the POLL softirq bit. The local_bh_disable()/enable() pair

	 * ensures that it is handled. Otherwise the current CPU could

	 * reach idle with the POLL softirq pending.

	 */

	local_bh_disable();

	local_irq_disable();

	list_splice_init(&per_cpu(blk_cpu_iopoll, cpu),

			 this_cpu_ptr(&blk_cpu_iopoll));

	__raise_softirq_irqoff(IRQ_POLL_SOFTIRQ);

	local_irq_enable();

	local_bh_enable();



	return 0;

}