[PATCH v3 1/3] drm/amdgpu: Fix out-of-bounds issue in user fence

Christian König christian.koenig at amd.com
Thu Dec 19 10:41:34 UTC 2024



Am 19.12.24 um 11:38 schrieb Arunpravin Paneer Selvam:
> Fix out-of-bounds issue in userq fence create when
> accessing the userq xa structure. Added a lock to
> protect the race condition.
>
> v2:(Christian)
>    - Acquire xa lock only for the xa_for_each blocks and
>      not for the kvmalloc_array() memory allocation part.
>
> v3:
>    - Replacing the kvmalloc_array() storage with xa_alloc()
>      solves the problem.
>
> BUG: KASAN: slab-out-of-bounds in amdgpu_userq_fence_create+0x726/0x880 [amdgpu]
> [  +0.000006] Call Trace:
> [  +0.000005]  <TASK>
> [  +0.000005]  dump_stack_lvl+0x6c/0x90
> [  +0.000011]  print_report+0xc4/0x5e0
> [  +0.000009]  ? srso_return_thunk+0x5/0x5f
> [  +0.000008]  ? kasan_complete_mode_report_info+0x26/0x1d0
> [  +0.000007]  ? amdgpu_userq_fence_create+0x726/0x880 [amdgpu]
> [  +0.000405]  kasan_report+0xdf/0x120
> [  +0.000009]  ? amdgpu_userq_fence_create+0x726/0x880 [amdgpu]
> [  +0.000405]  __asan_report_store8_noabort+0x17/0x20
> [  +0.000007]  amdgpu_userq_fence_create+0x726/0x880 [amdgpu]
> [  +0.000406]  ? __pfx_amdgpu_userq_fence_create+0x10/0x10 [amdgpu]
> [  +0.000408]  ? srso_return_thunk+0x5/0x5f
> [  +0.000008]  ? ttm_resource_move_to_lru_tail+0x235/0x4f0 [ttm]
> [  +0.000013]  ? srso_return_thunk+0x5/0x5f
> [  +0.000008]  amdgpu_userq_signal_ioctl+0xd29/0x1c70 [amdgpu]
> [  +0.000412]  ? __pfx_amdgpu_userq_signal_ioctl+0x10/0x10 [amdgpu]
> [  +0.000404]  ? try_to_wake_up+0x165/0x1840
> [  +0.000010]  ? __pfx_futex_wake_mark+0x10/0x10
> [  +0.000011]  drm_ioctl_kernel+0x178/0x2f0 [drm]
> [  +0.000050]  ? __pfx_amdgpu_userq_signal_ioctl+0x10/0x10 [amdgpu]
> [  +0.000404]  ? __pfx_drm_ioctl_kernel+0x10/0x10 [drm]
> [  +0.000043]  ? __kasan_check_read+0x11/0x20
> [  +0.000007]  ? srso_return_thunk+0x5/0x5f
> [  +0.000007]  ? __kasan_check_write+0x14/0x20
> [  +0.000008]  drm_ioctl+0x513/0xd20 [drm]
> [  +0.000040]  ? __pfx_amdgpu_userq_signal_ioctl+0x10/0x10 [amdgpu]
> [  +0.000407]  ? __pfx_drm_ioctl+0x10/0x10 [drm]
> [  +0.000044]  ? srso_return_thunk+0x5/0x5f
> [  +0.000007]  ? _raw_spin_lock_irqsave+0x99/0x100
> [  +0.000007]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10
> [  +0.000006]  ? __rseq_handle_notify_resume+0x188/0xc30
> [  +0.000008]  ? srso_return_thunk+0x5/0x5f
> [  +0.000008]  ? srso_return_thunk+0x5/0x5f
> [  +0.000006]  ? _raw_spin_unlock_irqrestore+0x27/0x50
> [  +0.000010]  amdgpu_drm_ioctl+0xcd/0x1d0 [amdgpu]
> [  +0.000388]  __x64_sys_ioctl+0x135/0x1b0
> [  +0.000009]  x64_sys_call+0x1205/0x20d0
> [  +0.000007]  do_syscall_64+0x4d/0x120
> [  +0.000008]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> [  +0.000007] RIP: 0033:0x7f7c3d31a94f
>
> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>
> ---
>   .../gpu/drm/amd/amdgpu/amdgpu_userq_fence.c   | 43 +++++++------------
>   .../gpu/drm/amd/amdgpu/amdgpu_userq_fence.h   |  3 +-
>   2 files changed, 17 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> index 2e7271362ace..4289bed6c1f7 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> @@ -122,10 +122,11 @@ int amdgpu_userq_fence_driver_alloc(struct amdgpu_device *adev,
>   
>   void amdgpu_userq_fence_driver_process(struct amdgpu_userq_fence_driver *fence_drv)
>   {
> +	struct amdgpu_userq_fence_driver *stored_fence_drv;
>   	struct amdgpu_userq_fence *userq_fence, *tmp;
>   	struct dma_fence *fence;
> +	unsigned long index;
>   	u64 rptr;
> -	int i;
>   
>   	if (!fence_drv)
>   		return;
> @@ -141,8 +142,8 @@ void amdgpu_userq_fence_driver_process(struct amdgpu_userq_fence_driver *fence_d
>   
>   		dma_fence_signal(fence);
>   
> -		for (i = 0; i < userq_fence->fence_drv_array_count; i++)
> -			amdgpu_userq_fence_driver_put(userq_fence->fence_drv_array[i]);
> +		xa_for_each(&userq_fence->fence_drv_xa, index, stored_fence_drv)
> +			amdgpu_userq_fence_driver_put(stored_fence_drv);
>   
>   		list_del(&userq_fence->link);
>   		dma_fence_put(fence);
> @@ -221,34 +222,24 @@ int amdgpu_userq_fence_create(struct amdgpu_usermode_queue *userq,
>   	dma_fence_init(fence, &amdgpu_userq_fence_ops, &userq_fence->lock,
>   		       fence_drv->context, seq);
>   
> +	xa_init_flags(&userq_fence->fence_drv_xa, XA_FLAGS_ALLOC);
> +
>   	amdgpu_userq_fence_driver_get(fence_drv);
>   	dma_fence_get(fence);
>   
>   	if (!xa_empty(&userq->fence_drv_xa)) {
>   		struct amdgpu_userq_fence_driver *stored_fence_drv;
> -		unsigned long index, count = 0;
> -		int i = 0;
> -
> -		xa_for_each(&userq->fence_drv_xa, index, stored_fence_drv)
> -			count++;
> -
> -		userq_fence->fence_drv_array =
> -			kvmalloc_array(count,
> -				       sizeof(struct amdgpu_userq_fence_driver *),
> -				       GFP_KERNEL);
> -
> -		if (userq_fence->fence_drv_array) {
> -			xa_for_each(&userq->fence_drv_xa, index, stored_fence_drv) {
> -				userq_fence->fence_drv_array[i] = stored_fence_drv;
> -				xa_erase(&userq->fence_drv_xa, index);
> -				i++;
> -			}
> +		unsigned long index_uq;
> +		u32 index_uf;
> +		int err;
> +
> +		xa_for_each(&userq->fence_drv_xa, index_uq, stored_fence_drv) {
> +			err = xa_alloc_irq(&userq_fence->fence_drv_xa, &index_uf,
> +					   stored_fence_drv, xa_limit_32b, GFP_KERNEL);

That is even worse than what was discussed before. Now you have two XAs 
and the second is incorrectly using GFP_KERNEL.

Regards,
Christian.

> +			if (err)
> +				return err;
>   		}
> -
> -		userq_fence->fence_drv_array_count = i;
> -	} else {
> -		userq_fence->fence_drv_array = NULL;
> -		userq_fence->fence_drv_array_count = 0;
> +		xa_destroy(&userq->fence_drv_xa);
>   	}
>   
>   	/* Check if hardware has already processed the job */
> @@ -300,8 +291,6 @@ static void amdgpu_userq_fence_free(struct rcu_head *rcu)
>   
>   	/* Release the fence driver reference */
>   	amdgpu_userq_fence_driver_put(fence_drv);
> -
> -	kvfree(userq_fence->fence_drv_array);
>   	kmem_cache_free(amdgpu_userq_fence_slab, userq_fence);
>   }
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.h
> index f1a90840ac1f..3283e5573d10 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.h
> @@ -37,9 +37,8 @@ struct amdgpu_userq_fence {
>   	 */
>   	spinlock_t lock;
>   	struct list_head link;
> -	unsigned long fence_drv_array_count;
> +	struct xarray fence_drv_xa;
>   	struct amdgpu_userq_fence_driver *fence_drv;
> -	struct amdgpu_userq_fence_driver **fence_drv_array;
>   };
>   
>   struct amdgpu_userq_fence_driver {



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