linux-kernel - Re: [PATCH] drm/radeon: don't evict if not initialized

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <d50c08e5-51d7-148c-464f-7699e6f6a115@amd.com>
Date:   Sun, 21 Mar 2021 14:26:27 +0100
From:   Christian König <christian.koenig@....com>
To:     Tong Zhang <ztong0001@...il.com>,
        Alex Deucher <alexander.deucher@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, amd-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/radeon: don't evict if not initialized



Am 20.03.21 um 21:10 schrieb Tong Zhang:
> TTM_PL_VRAM may not initialized at all when calling
> radeon_bo_evict_vram(). We need to check before doing eviction.
>
> [    2.160837] BUG: kernel NULL pointer dereference, address: 0000000000000020
> [    2.161212] #PF: supervisor read access in kernel mode
> [    2.161490] #PF: error_code(0x0000) - not-present page
> [    2.161767] PGD 0 P4D 0
> [    2.163088] RIP: 0010:ttm_resource_manager_evict_all+0x70/0x1c0 [ttm]
> [    2.168506] Call Trace:
> [    2.168641]  radeon_bo_evict_vram+0x1c/0x20 [radeon]
> [    2.168936]  radeon_device_fini+0x28/0xf9 [radeon]
> [    2.169224]  radeon_driver_unload_kms+0x44/0xa0 [radeon]
> [    2.169534]  radeon_driver_load_kms+0x174/0x210 [radeon]
> [    2.169843]  drm_dev_register+0xd9/0x1c0 [drm]
> [    2.170104]  radeon_pci_probe+0x117/0x1a0 [radeon]
>
> Signed-off-by: Tong Zhang <ztong0001@...il.com>
> ---
>   drivers/gpu/drm/radeon/radeon_object.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
> index 9b81786782de..04e9a8118b0e 100644
> --- a/drivers/gpu/drm/radeon/radeon_object.c
> +++ b/drivers/gpu/drm/radeon/radeon_object.c
> @@ -384,7 +384,9 @@ int radeon_bo_evict_vram(struct radeon_device *rdev)
>   	}
>   #endif
>   	man = ttm_manager_type(bdev, TTM_PL_VRAM);
> -	return ttm_resource_manager_evict_all(bdev, man);
> +	if (man)
> +		return ttm_resource_manager_evict_all(bdev, man);
> +	return 0;

You should probably code this the other way around, e.g.

If (!man)
     return 0;
...

Apart from that looks good to me.

Christian.

>   }
>   
>   void radeon_bo_force_delete(struct radeon_device *rdev)