linux-kernel - Re: [PATCH] drm/amdgpu: Fix resource leak on probe error path

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Message-ID: <nycvar.YFH.7.76.2107011030030.18969@cbobk.fhfr.pm>
Date:   Thu, 1 Jul 2021 10:32:43 +0200 (CEST)
From:   Jiri Kosina <jikos@...nel.org>
To:     Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        David Airlie <airlied@...ux.ie>
cc:     amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, Vojtech Pavlik <vojtech@....cz>
Subject: Re: [PATCH] drm/amdgpu: Fix resource leak on probe error path

On Thu, 24 Jun 2021, Jiri Kosina wrote:

> From: Jiri Kosina <jkosina@...e.cz>
> 
> This reverts commit 4192f7b5768912ceda82be2f83c87ea7181f9980.
> 
> It is not true (as stated in the reverted commit changelog) that we never 
> unmap the BAR on failure; it actually does happen properly on 
> amdgpu_driver_load_kms() -> amdgpu_driver_unload_kms() -> 
> amdgpu_device_fini() error path.
> 
> What's worse, this commit actually completely breaks resource freeing on 
> probe failure (like e.g. failure to load microcode), as 
> amdgpu_driver_unload_kms() notices adev->rmmio being NULL and bails too 
> early, leaving all the resources that'd normally be freed in 
> amdgpu_acpi_fini() and amdgpu_device_fini() still hanging around, leading 
> to all sorts of oopses when someone tries to, for example, access the 
> sysfs and procfs resources which are still around while the driver is 
> gone.
> 
> Fixes: 4192f7b57689 ("drm/amdgpu: unmap register bar on device init failure")
> Reported-by: Vojtech Pavlik <vojtech@....cz>
> Signed-off-by: Jiri Kosina <jkosina@...e.cz>

Friendly ping on this one (as it's easily triggerable in the wild by just 
missing proper firwmare).

Thanks.

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 57ec108b5972..0f1c0e17a587 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3414,13 +3414,13 @@ int amdgpu_device_init(struct amdgpu_device *adev,
>  	r = amdgpu_device_get_job_timeout_settings(adev);
>  	if (r) {
>  		dev_err(adev->dev, "invalid lockup_timeout parameter syntax\n");
> -		goto failed_unmap;
> +		return r;
>  	}
>  
>  	/* early init functions */
>  	r = amdgpu_device_ip_early_init(adev);
>  	if (r)
> -		goto failed_unmap;
> +		return r;
>  
>  	/* doorbell bar mapping and doorbell index init*/
>  	amdgpu_device_doorbell_init(adev);
> @@ -3646,10 +3646,6 @@ int amdgpu_device_init(struct amdgpu_device *adev,
>  failed:
>  	amdgpu_vf_error_trans_all(adev);
>  
> -failed_unmap:
> -	iounmap(adev->rmmio);
> -	adev->rmmio = NULL;
> -
>  	return r;
>  }
>  
> -- 
> 2.12.3
> 
> 

-- 
Jiri Kosina
SUSE Labs