Re: [PATCH 1/1] drm/hyperv: Fix address space leak when Hyper-V DRM device is removed

[Thomas Zimmermann <tzimmermann@suse.de>]

Hi

Am 10.02.25 um 20:34 schrieb mhkelley58@gmail.com:
> From: Michael Kelley <mhklinux@outlook.com>
>
> When a Hyper-V DRM device is probed, the driver allocates MMIO space for
> the vram, and maps it cacheable. If the device removed, or in the error
> path for device probing, the MMIO space is released but no unmap is done.
> Consequently the kernel address space for the mapping is leaked.
>
> Fix this by adding iounmap() calls in the device removal path, and in the
> error path during device probing.

Could this driver use devm_ helpers for iomap operations? That should 
fix the issue automatically.

Best regards
Thomas

>
> Fixes: f1f63cbb705d ("drm/hyperv: Fix an error handling path in hyperv_vmbus_probe()")
> Fixes: a0ab5abced55 ("drm/hyperv : Removing the restruction of VRAM allocation with PCI bar size")
> Signed-off-by: Michael Kelley <mhklinux@outlook.com>
> ---
>   drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> index e0953777a206..b491827941f1 100644
> --- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> +++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> @@ -156,6 +156,7 @@ static int hyperv_vmbus_probe(struct hv_device *hdev,
>   	return 0;
>   
>   err_free_mmio:
> +	iounmap(hv->vram);
>   	vmbus_free_mmio(hv->mem->start, hv->fb_size);
>   err_vmbus_close:
>   	vmbus_close(hdev->channel);
> @@ -174,6 +175,7 @@ static void hyperv_vmbus_remove(struct hv_device *hdev)
>   	vmbus_close(hdev->channel);
>   	hv_set_drvdata(hdev, NULL);
>   
> +	iounmap(hv->vram);
>   	vmbus_free_mmio(hv->mem->start, hv->fb_size);
>   }
>   

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)