From cfdb14570c73fd71252fdda3be619399ed3c341d Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 2 Apr 2020 21:16:30 +0200 Subject: [PATCH 056/166] irq_poll: Use raise_softirq_irqoff() in cpu_dead notifier __raise_softirq_irqoff() adds a bit to the pending sofirq mask and this is it. The softirq won't be handled in a deterministic way but randomly when an interrupt fires and handles softirq in its irq_exit() routine or if something randomly checks and handles pending softirqs in the call chain before the CPU goes idle. Add a local_bh_disable/enable() around the IRQ-off section which will handle pending softirqs. Signed-off-by: Sebastian Andrzej Siewior Link: https://lkml.kernel.org/r/20210930103754.2128949-1-bigeasy@linutronix.de --- lib/irq_poll.c | 2 ++ 1 file changed, 2 insertions(+) Index: linux-5.15.32-rt39/lib/irq_poll.c =================================================================== --- linux-5.15.32-rt39.orig/lib/irq_poll.c +++ linux-5.15.32-rt39/lib/irq_poll.c @@ -191,11 +191,13 @@ static int irq_poll_cpu_dead(unsigned in * If a CPU goes away, splice its entries to the current CPU * and trigger a run of the softirq */ + 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; }