[PATCH 02/10] drm/amdgpu: Protect the amdgpu_bo_list list with a mutex v2

[Christian König]

From: Luben Tuikov <luben.tui...@amd.com>

Protect the struct amdgpu_bo_list with a mutex. This is used during command
submission in order to avoid buffer object corruption as recorded in
the link below.

v2 (chk): Keep the mutex looked for the whole CS to avoid using the
          list from multiple CS threads at the same time.

Suggested-by: Christian König <christian.koe...@amd.com>
Cc: Alex Deucher <alexander.deuc...@amd.com>
Cc: Andrey Grodzovsky <andrey.grodzov...@amd.com>
Cc: Vitaly Prosyak <vitaly.pros...@amd.com>
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2048
Signed-off-by: Luben Tuikov <luben.tui...@amd.com>
Signed-off-by: Christian König <christian.koe...@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c |  3 ++-
 drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h |  4 ++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c      | 16 +++++++++++++---
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
index 714178f1b6c6..2168163aad2d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
@@ -40,7 +40,7 @@ static void amdgpu_bo_list_free_rcu(struct rcu_head *rcu)
 {
        struct amdgpu_bo_list *list = container_of(rcu, struct amdgpu_bo_list,
                                                   rhead);
-
+       mutex_destroy(&list->bo_list_mutex);
        kvfree(list);
 }
 
@@ -136,6 +136,7 @@ int amdgpu_bo_list_create(struct amdgpu_device *adev, 
struct drm_file *filp,
 
        trace_amdgpu_cs_bo_status(list->num_entries, total_size);
 
+       mutex_init(&list->bo_list_mutex);
        *result = list;
        return 0;
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
index 529d52a204cf..9caea1688fc3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
@@ -47,6 +47,10 @@ struct amdgpu_bo_list {
        struct amdgpu_bo *oa_obj;
        unsigned first_userptr;
        unsigned num_entries;
+
+       /* Protect access during command submission.
+        */
+       struct mutex bo_list_mutex;
 };
 
 int amdgpu_bo_list_get(struct amdgpu_fpriv *fpriv, int id,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index b28af04b0c3e..d8f1335bc68f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -519,6 +519,8 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
                        return r;
        }
 
+       mutex_lock(&p->bo_list->bo_list_mutex);
+
        /* One for TTM and one for the CS job */
        amdgpu_bo_list_for_each_entry(e, p->bo_list)
                e->tv.num_shared = 2;
@@ -651,6 +653,7 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
                        kvfree(e->user_pages);
                        e->user_pages = NULL;
                }
+               mutex_unlock(&p->bo_list->bo_list_mutex);
        }
        return r;
 }
@@ -690,9 +693,11 @@ static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser 
*parser, int error,
 {
        unsigned i;
 
-       if (error && backoff)
+       if (error && backoff) {
                ttm_eu_backoff_reservation(&parser->ticket,
                                           &parser->validated);
+               mutex_unlock(&parser->bo_list->bo_list_mutex);
+       }
 
        for (i = 0; i < parser->num_post_deps; i++) {
                drm_syncobj_put(parser->post_deps[i].syncobj);
@@ -832,12 +837,16 @@ static int amdgpu_cs_vm_handling(struct amdgpu_cs_parser 
*p)
                        continue;
 
                r = amdgpu_vm_bo_update(adev, bo_va, false);
-               if (r)
+               if (r) {
+                       mutex_unlock(&p->bo_list->bo_list_mutex);
                        return r;
+               }
 
                r = amdgpu_sync_fence(&p->job->sync, bo_va->last_pt_update);
-               if (r)
+               if (r) {
+                       mutex_unlock(&p->bo_list->bo_list_mutex);
                        return r;
+               }
        }
 
        r = amdgpu_vm_handle_moved(adev, vm);
@@ -1278,6 +1287,7 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
 
        ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence);
        mutex_unlock(&p->adev->notifier_lock);
+       mutex_unlock(&p->bo_list->bo_list_mutex);
 
        return 0;
 
-- 
2.25.1