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Subject: Re: [PATCH] drm/amdgpu/acp: Fix slab-out-of-bounds in mfd_add_device
 in acp_hw_init
To:     Daniel Kurtz <djkurtz@chromium.org>
Cc:     Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        David Airlie <airlied@linux.ie>,
        Vijendar Mukunda <Vijendar.Mukunda@amd.com>,
        Jason Clinton <jclinton@chromium.org>,
        "open list:RADEON and AMDGPU DRM DRIVERS" 
        <amd-gfx@lists.freedesktop.org>,
        "open list:DRM DRIVERS" <dri-devel@lists.freedesktop.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20180413161601.109431-1-djkurtz@chromium.org>
From:   "Agrawal, Akshu" <Akshu.Agrawal@amd.com>
Message-ID: <6e46904a-d721-d583-8ab5-82cb07df7934@amd.com>
Date:   Mon, 16 Apr 2018 09:17:46 +0530
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On 4/13/2018 9:45 PM, Daniel Kurtz wrote:
> Commit 51f7415039d4 ("drm/amd/amdgpu: creating two I2S instances for
> stoney/cz") added support for the "BT_I2S" ACP i2s channel.  As part of
> this change, one additional acp resource was added, but the "num_resource"
> count was accidentally incremented by 2.
> 
> This incorrect count eventually causes mfd_add_device() to try to access
> an invalid memory address (the location of non-existent resource 5.
> 
> This fault was detected by running a KASAN enabled kernel, which produced
> the following splat at boot:
> 
> [    6.612987] ==================================================================
> [    6.613509] BUG: KASAN: slab-out-of-bounds in mfd_add_device+0x4bc/0x7a7
> [    6.613509] Read of size 8 at addr ffff880107d4dc58 by task swapper/0/1
> [    6.613509]
> [    6.613509] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.14.33 #349
> [    6.613509] Hardware name: Google Grunt/Grunt, BIOS Google_Grunt.10543.0.2018_04_03_1812 04/02/2018
> [    6.613509] Call Trace:
> [    6.613509]  dump_stack+0x4d/0x63
> [    6.613509]  print_address_description+0x80/0x2d6
> [    6.613509]  ? mfd_add_device+0x4bc/0x7a7
> [    6.613509]  kasan_report+0x255/0x295
> [    6.613509]  mfd_add_device+0x4bc/0x7a7
> [    6.613509]  ? kasan_kmalloc+0x99/0xa8
> [    6.613509]  ? mfd_add_devices+0x58/0xe4
> [    6.613509]  ? __kmalloc+0x154/0x178
> [    6.613509]  mfd_add_devices+0xa5/0xe4
> [    6.613509]  acp_hw_init+0x92e/0xc4a
> [    6.613509]  amdgpu_device_init+0x1dfb/0x22a2
> [    6.613509]  ? kmalloc_order+0x53/0x5d
> [    6.613509]  ? kmalloc_order_trace+0x23/0xb3
> [    6.613509]  amdgpu_driver_load_kms+0xce/0x267
> [    6.613509]  drm_dev_register+0x169/0x2fb
> [    6.613509]  amdgpu_pci_probe+0x217/0x242
> [    6.613509]  pci_device_probe+0x101/0x18e
> [    6.613509]  driver_probe_device+0x1dd/0x419
> [    6.613509]  ? ___might_sleep+0x80/0x1b6
> [    6.613509]  __driver_attach+0x9f/0xc9
> [    6.613509]  ? driver_probe_device+0x419/0x419
> [    6.613509]  bus_for_each_dev+0xbc/0xe1
> [    6.613509]  bus_add_driver+0x189/0x2c0
> [    6.613509]  driver_register+0x108/0x156
> [    6.613509]  ? ttm_init+0x67/0x67
> [    6.613509]  do_one_initcall+0xb2/0x161
> [    6.613509]  kernel_init_freeable+0x25a/0x308
> [    6.613509]  ? rest_init+0xcc/0xcc
> [    6.613509]  kernel_init+0x11/0x10d
> [    6.613509]  ? rest_init+0xcc/0xcc
> [    6.613509]  ret_from_fork+0x22/0x40
> [    6.613509]
> [    6.613509] Allocated by task 1:
> [    6.613509]  save_stack+0x46/0xce
> [    6.613509]  kasan_kmalloc+0x99/0xa8
> [    6.613509]  kmem_cache_alloc_trace+0x11a/0x13e
> [    6.613509]  acp_hw_init+0x210/0xc4a
> [    6.613509]  amdgpu_device_init+0x1dfb/0x22a2
> [    6.613509]  amdgpu_driver_load_kms+0xce/0x267
> [    6.613509]  drm_dev_register+0x169/0x2fb
> [    6.613509]  amdgpu_pci_probe+0x217/0x242
> [    6.613509]  pci_device_probe+0x101/0x18e
> [    6.613509]  driver_probe_device+0x1dd/0x419
> [    6.613509]  __driver_attach+0x9f/0xc9
> [    6.613509]  bus_for_each_dev+0xbc/0xe1
> [    6.613509]  bus_add_driver+0x189/0x2c0
> [    6.613509]  driver_register+0x108/0x156
> [    6.613509]  do_one_initcall+0xb2/0x161
> [    6.613509]  kernel_init_freeable+0x25a/0x308
> [    6.613509]  kernel_init+0x11/0x10d
> [    6.613509]  ret_from_fork+0x22/0x40
> [    6.613509]
> [    6.613509] Freed by task 0:
> [    6.613509] (stack is not available)
> [    6.613509]
> [    6.613509] The buggy address belongs to the object at ffff880107d4db08
> [    6.613509]  which belongs to the cache kmalloc-512 of size 512
> [    6.613509] The buggy address is located 336 bytes inside of
> [    6.613509]  512-byte region [ffff880107d4db08, ffff880107d4dd08)
> [    6.613509] The buggy address belongs to the page:
> [    6.613509] page:ffffea00041f5300 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
> [    6.613509] flags: 0x8000000000008100(slab|head)
> [    6.613509] raw: 8000000000008100 0000000000000000 0000000000000000 0000000100120012
> [    6.613509] raw: ffffea0004208520 ffff88010b001680 ffff88010b002cc0 0000000000000000
> [    6.613509] page dumped because: kasan: bad access detected
> [    6.613509]
> [    6.613509] Memory state around the buggy address:
> [    6.613509]  ffff880107d4db00: fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [    6.613509]  ffff880107d4db80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [    6.613509] >ffff880107d4dc00: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
> [    6.613509]                                                     ^
> [    6.613509]  ffff880107d4dc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> [    6.613509]  ffff880107d4dd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> [    6.613509] ==================================================================
> 
> Fixes: 51f7415039d4 ("drm/amd/amdgpu: creating two I2S instances for stoney/cz")
> Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Acked-by: Akshu Agrawal <akshu.agrawal@amd.com>

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c
> index 20f20079935b..42f0d60cf3f4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c
> @@ -402,7 +402,7 @@ static int acp_hw_init(void *handle)
>   	adev->acp.acp_res[4].end = adev->acp.acp_res[4].start;
>   
>   	adev->acp.acp_cell[0].name = "acp_audio_dma";
> -	adev->acp.acp_cell[0].num_resources = 6;
> +	adev->acp.acp_cell[0].num_resources = 5;
>   	adev->acp.acp_cell[0].resources = &adev->acp.acp_res[0];
>   	adev->acp.acp_cell[0].platform_data = &adev->asic_type;
>   	adev->acp.acp_cell[0].pdata_size = sizeof(adev->asic_type);
>