Re: [PATCH] drm/amdgpu/acp: Fix slab-out-of-bounds in mfd_add_device in acp_hw_init

From: Agrawal, Akshu
Date: Sun Apr 15 2018 - 23:48:21 EST




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@xxxxxxxxxxxx>
Acked-by: Akshu Agrawal <akshu.agrawal@xxxxxxx>

---
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);