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

Arunpravin Paneer Selvam Arunpravin.PaneerSelvam at amd.com
Thu Dec 19 10:38:22 UTC 2024


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);
+			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 {
-- 
2.25.1



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