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Message-ID: <762b7c68-5ae3-b27e-1018-b930de61b99e@redhat.com>
Date:   Wed, 23 Nov 2022 09:41:06 +0100
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Reply-To: eric.auger@redhat.com
Subject: Re: [PATCH] vfio/platform: Remove the ACPI buffer memory to fix
 memory leak
Content-Language: en-US
To:     Hanjun Guo <guohanjun@huawei.com>,
        Alex Williamson <alex.williamson@redhat.com>
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        Sinan Kaya <okaya@codeaurora.org>
References: <1669116598-25761-1-git-send-email-guohanjun@huawei.com>
From:   Eric Auger <eric.auger@redhat.com>
In-Reply-To: <1669116598-25761-1-git-send-email-guohanjun@huawei.com>
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Hi,

On 11/22/22 12:29, Hanjun Guo wrote:
> The ACPI buffer memory (buffer.pointer) returned by acpi_evaluate_object()
> is not used after the call of _RST method, so it leads to memory leak.
>
> For the calling of ACPI _RST method, we don't need to pass a buffer
> for acpi_evaluate_object(), we can just pass NULL and remove the ACPI
> buffer memory in vfio_platform_acpi_call_reset(), then we don't need to
> free the memory and no memory leak.
>
> Fixes: d30daa33ec1d ("vfio: platform: call _RST method when using ACPI")
> Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
> ---
>  drivers/vfio/platform/vfio_platform_common.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> index 55dc4f4..1a0a238 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -72,12 +72,11 @@ static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
>  				  const char **extra_dbg)
>  {
>  #ifdef CONFIG_ACPI
> -	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
>  	struct device *dev = vdev->device;
>  	acpi_handle handle = ACPI_HANDLE(dev);
>  	acpi_status acpi_ret;
>  
> -	acpi_ret = acpi_evaluate_object(handle, "_RST", NULL, &buffer);
> +	acpi_ret = acpi_evaluate_object(handle, "_RST", NULL, NULL);
>  	if (ACPI_FAILURE(acpi_ret)) {
>  		if (extra_dbg)
>  			*extra_dbg = acpi_format_exception(acpi_ret);
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thank you for the fix!

Eric