[PATCH v2] drm/amdgpu: Protect the validate list with a mutex

[Luben Tuikov]

Protect the parser's validate list with a mutex in order to avoid buffer
object corruption as recorded in the link below.

Cc: Christian König <christian.koenig at amd.com>
Cc: Alex Deucher <Alexander.Deucher at amd.com>
Cc: Andrey Grodzovsky <Andrey.Grodzovsky at amd.com>
Cc: Vitaly Prosyak <Vitaly.Prosyak at amd.com>
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2048
Signed-off-by: Luben Tuikov <luben.tuikov at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 30 ++++++++++++++++++++------
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.h |  4 ++++
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 36ac1f1d11e6b4..0be0bf17c05420 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -498,6 +498,7 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
 	struct amdgpu_bo *oa;
 	int r;
 
+	mutex_init(&p->mutex_validated);
 	INIT_LIST_HEAD(&p->validated);
 
 	/* p->bo_list could already be assigned if AMDGPU_CHUNK_ID_BO_HANDLES is present */
@@ -521,13 +522,15 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
 	amdgpu_bo_list_for_each_entry(e, p->bo_list)
 		e->tv.num_shared = 2;
 
-	amdgpu_bo_list_get_list(p->bo_list, &p->validated);
-
 	INIT_LIST_HEAD(&duplicates);
+
+	mutex_lock(&p->mutex_validated);
+	amdgpu_bo_list_get_list(p->bo_list, &p->validated);
 	amdgpu_vm_get_pd_bo(&fpriv->vm, &p->validated, &p->vm_pd);
 
 	if (p->uf_entry.tv.bo && !ttm_to_amdgpu_bo(p->uf_entry.tv.bo)->parent)
 		list_add(&p->uf_entry.tv.head, &p->validated);
+	mutex_unlock(&p->mutex_validated);
 
 	/* Get userptr backing pages. If pages are updated after registered
 	 * in amdgpu_gem_userptr_ioctl(), amdgpu_cs_list_validate() will do
@@ -563,8 +566,11 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
 		e->user_invalidated = userpage_invalidated;
 	}
 
+	mutex_lock(&p->mutex_validated);
 	r = ttm_eu_reserve_buffers(&p->ticket, &p->validated, true,
 				   &duplicates);
+	mutex_unlock(&p->mutex_validated);
+
 	if (unlikely(r != 0)) {
 		if (r != -ERESTARTSYS)
 			DRM_ERROR("ttm_eu_reserve_buffers failed.\n");
@@ -607,11 +613,15 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
 		goto error_validate;
 	}
 
+	mutex_lock(&p->mutex_validated);
 	r = amdgpu_cs_list_validate(p, &duplicates);
-	if (r)
+	if (r) {
+		mutex_unlock(&p->mutex_validated);
 		goto error_validate;
+	}
 
 	r = amdgpu_cs_list_validate(p, &p->validated);
+	mutex_unlock(&p->mutex_validated);
 	if (r)
 		goto error_validate;
 
@@ -648,7 +658,9 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
 			dma_fence_chain_free(e->chain);
 			e->chain = NULL;
 		}
+		mutex_lock(&p->mutex_validated);
 		ttm_eu_backoff_reservation(&p->ticket, &p->validated);
+		mutex_unlock(&p->mutex_validated);
 	}
 
 out_free_user_pages:
@@ -670,8 +682,9 @@ static int amdgpu_cs_sync_rings(struct amdgpu_cs_parser *p)
 {
 	struct amdgpu_fpriv *fpriv = p->filp->driver_priv;
 	struct amdgpu_bo_list_entry *e;
-	int r;
+	int r = 0;
 
+	mutex_lock(&p->mutex_validated);
 	list_for_each_entry(e, &p->validated, tv.head) {
 		struct amdgpu_bo *bo = ttm_to_amdgpu_bo(e->tv.bo);
 		struct dma_resv *resv = bo->tbo.base.resv;
@@ -682,9 +695,10 @@ static int amdgpu_cs_sync_rings(struct amdgpu_cs_parser *p)
 		r = amdgpu_sync_resv(p->adev, &p->job->sync, resv, sync_mode,
 				     &fpriv->vm);
 		if (r)
-			return r;
+			break;
 	}
-	return 0;
+	mutex_unlock(&p->mutex_validated);
+	return r;
 }
 
 /**
@@ -709,8 +723,10 @@ static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser, int error,
 			e->chain = NULL;
 		}
 
+		mutex_lock(&parser->mutex_validated);
 		ttm_eu_backoff_reservation(&parser->ticket,
 					   &parser->validated);
+		mutex_unlock(&parser->mutex_validated);
 	}
 
 	for (i = 0; i < parser->num_post_deps; i++) {
@@ -1307,7 +1323,9 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
 		e->chain = NULL;
 	}
 
+	mutex_lock(&p->mutex_validated);
 	ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence);
+	mutex_unlock(&p->mutex_validated);
 	mutex_unlock(&p->adev->notifier_lock);
 
 	return 0;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.h
index 30ecc4917f811d..284d1c03d65d0b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.h
@@ -59,6 +59,10 @@ struct amdgpu_cs_parser {
 	struct amdgpu_bo_list		*bo_list;
 	struct amdgpu_mn		*mn;
 	struct amdgpu_bo_list_entry	vm_pd;
+
+	/* Protect access to list "valided" below.
+	 */
+	struct mutex                    mutex_validated;
 	struct list_head		validated;
 	struct dma_fence		*fence;
 	uint64_t			bytes_moved_threshold;

base-commit: ab7e60938be74e21c723223e7eb96cac7b441e5e
-- 
2.36.1.74.g277cf0bc36