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Message-ID: <20201026195308.wsbk7xy57wuzfbao@linutronix.de>
Date: Mon, 26 Oct 2020 20:53:08 +0100
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: Mike Galbraith <efault@....de>
Cc: Hillf Danton <hdanton@...a.com>,
Thomas Gleixner <tglx@...utronix.de>,
LKML <linux-kernel@...r.kernel.org>,
linux-rt-users <linux-rt-users@...r.kernel.org>,
Steven Rostedt <rostedt@...dmis.org>,
Ben Skeggs <bskeggs@...hat.com>
Subject: Re: kvm+nouveau induced lockdep gripe
On 2020-10-26 20:15:23 [+0100], Mike Galbraith wrote:
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/pci/base.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/pci/base.c
> @@ -116,7 +116,17 @@ nvkm_pci_oneinit(struct nvkm_subdev *sub
> return ret;
> }
>
> + /*
> + * Scheduler code taking cpuset_rwsem during irq thread initialization sets
> + * up a cpuset_rwsem vs mm->mmap_lock circular dependency gripe upon later
> + * cpuset usage. It's harmless, tell lockdep there's nothing to see here.
> + */
> + if (force_irqthreads)
> + lockdep_off();
> ret = request_irq(pdev->irq, nvkm_pci_intr, IRQF_SHARED, "nvkm", pci);
> + if (force_irqthreads)
> + lockdep_on();
> +
> if (ret)
> return ret;
>
Could you try this, please?
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1155,6 +1155,8 @@ static int irq_thread(void *data)
irqreturn_t (*handler_fn)(struct irq_desc *desc,
struct irqaction *action);
+ sched_set_fifo(current);
+
if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
&action->thread_flags))
handler_fn = irq_forced_thread_fn;
@@ -1320,8 +1322,6 @@ setup_irq_thread(struct irqaction *new,
if (IS_ERR(t))
return PTR_ERR(t);
- sched_set_fifo(t);
-
/*
* We keep the reference to the task struct even if
* the thread dies to avoid that the interrupt code
Sebastian
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