linux-kernel - Re: [PATCH 2/2] KVM: x86: flush pending lapic jump label updates on module unload

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Message-ID: <20161219142404.GA21302@potion>
Date:   Mon, 19 Dec 2016 15:24:05 +0100
From:   Radim Krčmář <rkrcmar@...hat.com>
To:     David Matlack <dmatlack@...gle.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        pbonzini@...hat.com, peterz@...radead.org, haokexin@...il.com,
        mpe@...erman.id.au, yongjun_wei@...ndmicro.com.cn,
        rusty@...tcorp.com.au, jbaron@...mai.com
Subject: Re: [PATCH 2/2] KVM: x86: flush pending lapic jump label updates on
 module unload

2016-12-16 14:30-0800, David Matlack:
> KVM's lapic emulation uses static_key_deferred (apic_{hw,sw}_disabled).
> These are implemented with delayed_work structs which can still be
> pending when the KVM module is unloaded. We've seen this cause kernel
> panics when the kvm_intel module is quickly reloaded.
> 
> Use the new static_key_deferred_flush() API to flush pending updates on
> module unload.
> 
> Signed-off-by: David Matlack <dmatlack@...gle.com>
> ---

Oh, this forgotten bug.  I guess that patches to do this automatically
from generic module unload code would be over-engineering it ...

Reviewed-by: Radim Krčmář <rkrcmar@...hat.com>

Thanks.