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

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Message-ID: <20190618203348.GA16699@zn.tnic>
Date:   Tue, 18 Jun 2019 22:34:16 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>, x86@...nel.org
Subject: Re: [PATCH] x86/microcode: Fix the microcode load on CPU hotplug for
 real

On Tue, Jun 18, 2019 at 10:31:40PM +0200, Thomas Gleixner 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@...utronix.de>
> Cc: stable@...r.kernel.org
> ---
>  arch/x86/kernel/cpu/microcode/core.c |   15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)

Acked-by: Borislav Petkov <bp@...e.de>

Thanks for fixing that!

-- 
Regards/Gruss,
    Boris.

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