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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     Dongliang Mu <dzm91@hust.edu.cn>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>
Cc:     mudongliang <mudongliangabcd@gmail.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: kvm: remove NULL check before kfree
In-Reply-To: <20220614085035.122521-1-dzm91@hust.edu.cn>
References: <20220614085035.122521-1-dzm91@hust.edu.cn>
Date:   Tue, 14 Jun 2022 14:01:54 +0200
Message-ID: <87zgifihcd.fsf@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Dongliang Mu <dzm91@hust.edu.cn> writes:

> From: mudongliang <mudongliangabcd@gmail.com>
>
> kfree can handle NULL pointer as its argument.
> According to coccinelle isnullfree check, remove NULL check
> before kfree operation.
>
> Signed-off-by: mudongliang <mudongliangabcd@gmail.com>
> ---
>  arch/x86/kernel/kvm.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index 1a3658f7e6d9..d4e48b4a438b 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -236,8 +236,7 @@ void kvm_async_pf_task_wake(u32 token)
>  	raw_spin_unlock(&b->lock);
>  
>  	/* A dummy token might be allocated and ultimately not used.  */
> -	if (dummy)
> -		kfree(dummy);
> +	kfree(dummy);
>  }
>  EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>

-- 
Vitaly