Re: [PATCH] x86/microcode: Fix the microcode load on CPU hotplug for real

Evan Green
2019-06-26T17:20:55Z

On Tue, Jun 18, 2019 at 1:31 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> A recent change moved the microcode loader hotplug callback into the early
> startup phase, which is running with interrupts disabled. It missed that
> the callbacks invoke sysfs functions which might sleep causing nice 'might
> sleep' splats with proper debugging enabled.
>
> Split the callbacks and only load the microcode in the early startup phase
> and move the sysfs handling back into the later threaded and preemptible
> bringup phase where it was before.
>
> Fixes: 78f4e932f776 ("x86/microcode, cpuhotplug: Add a microcode loader CPU hotplug callback")
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

I ran into the bug fixed by this. For 4.19:
Tested-by: Evan Green <evgreen@chromium.org>