Messages in this thread Patch in this message | | | Date | Mon, 4 Sep 2017 11:23:01 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH] IRQ, cpu-hotplug: Fix a race between CPU hotplug and IRQ desc alloc/free |
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On Mon, 4 Sep 2017, Huang, Ying wrote: > diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c > index 638eb9c83d9f..af9029625271 100644 > --- a/kernel/irq/cpuhotplug.c ry> +++ b/kernel/irq/cpuhotplug.c > @@ -129,10 +129,13 @@ void irq_migrate_all_off_this_cpu(void) > struct irq_desc *desc; > unsigned int irq; > > + irq_lock_sparse();
You cannot take that lock here as irq_migrate_all_off_this_cpu() is called with interrupts disabled.
The protection in takedown_cpus() is wrong. Patch below.
Thanks,
tglx ----
--- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -642,13 +642,13 @@ static int takedown_cpu(unsigned int cpu wait_for_completion(&st->done); BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); - /* Interrupts are moved away from the dying cpu, reenable alloc/free */ - irq_unlock_sparse(); - hotplug_cpu__broadcast_tick_pull(cpu); /* This actually kills the CPU. */ __cpu_die(cpu); + /* Interrupts are moved away from the dying cpu, reenable alloc/free */ + irq_unlock_sparse(); + tick_cleanup_dead_cpu(cpu); return 0; }
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