linux-kernel - Re: [PATCH 1/4] KVM: x86/mmu: Fix RCU usage in handle_removed_tdp_mmu

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Message-ID: <YEuKx6ZveaT5RgAs@google.com>
Date:   Fri, 12 Mar 2021 07:37:43 -0800
From:   Sean Christopherson <seanjc@...gle.com>
To:     Ben Gardon <bgardon@...gle.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Peter Shier <pshier@...gle.com>,
        Jim Mattson <jmattson@...gle.com>
Subject: Re: [PATCH 1/4] KVM: x86/mmu: Fix RCU usage in
 handle_removed_tdp_mmu_page

On Thu, Mar 11, 2021, Ben Gardon wrote:
> The pt passed into handle_removed_tdp_mmu_page does not need RCU
> protection, as it is not at any risk of being freed by another thread at
> that point. However, the implicit cast from tdp_sptep_t to u64 * dropped
> the __rcu annotation without a proper rcu_derefrence. Fix this by
> passing the pt as a tdp_ptep_t and then rcu_dereferencing it in
> the function.
> 
> Suggested-by: Sean Christopherson <seanjc@...gle.com>
> Reported-by: kernel test robot <lkp@...xxxxxx>

Should be <lkp@...el.com>.  Looks like you've been taking pointers from Paolo :-)

https://lkml.org/lkml/2019/6/17/1210

Other than that,

Reviewed-by: Sean Christopherson <seanjc@...gle.com>

> Signed-off-by: Ben Gardon <bgardon@...gle.com>