GPencil: Crash when opening a file that has a gpencil data block with layer transforms #96216

New Issue

Falk David · 2022-03-07T13:12:53+01:00

Falk David commented

2022-03-07 13:12:53 +01:00

System Information
Operating system: Linux-5.15.23-76051523-generic-x86_64-with-glibc2.34 64 Bits
Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.54

Blender Version
Broken: version: 3.2.0 Alpha, branch: master
Worked: 3.1

Caused by 7ca13eef7c

Short description of error
Blender crashes on opening a file that was saved with layer transforms.

Exact steps for others to reproduce the error

Open Blender with the 2D Animation template.
Change the layer transform in the object data properties panel under "Transform".

Save the file and reopen it -> Blender crashes.

or

Open test file -> Blender crashes.

gpencil-orig-pointers-bug.blend

Investigation

The crash occurs when a grease pencil data-block is expanded for the first time and then tries to access the gpf->runtime.gpf_orig pointer in copy_frame_to_eval_cb from BKE_gpencil_prepare_eval_data. That pointer is NULL.

This is because in deg_update_copy_on_write_datablock when we do a copy on write, we only call BKE_gpencil_data_update_orig_pointers in GPencilBackup::restore_to_gpencil if a backup has been created. But RuntimeBackup::init_from_id returns early if deg_copy_on_write_is_expanded is false.

Maybe the solution is to add some logic to update_id_after_copy to make sure the runtime orig pointers are updated.

**System Information** Operating system: Linux-5.15.23-76051523-generic-x86_64-with-glibc2.34 64 Bits Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.54 **Blender Version** Broken: version: 3.2.0 Alpha, branch: master Worked: 3.1 Caused by 7ca13eef7c **Short description of error** Blender crashes on opening a file that was saved with layer transforms. **Exact steps for others to reproduce the error** - Open Blender with the 2D Animation template. - Change the layer transform in the object data properties panel under "Transform". # Save the file and reopen it -> Blender crashes. or # Open test file -> Blender crashes. [gpencil-orig-pointers-bug.blend](https://archive.blender.org/developer/F12900604/gpencil-orig-pointers-bug.blend) **Investigation** The crash occurs when a grease pencil data-block is expanded for the first time and then tries to access the `gpf->runtime.gpf_orig` pointer in `copy_frame_to_eval_cb` from `BKE_gpencil_prepare_eval_data`. That pointer is `NULL`. This is because in `deg_update_copy_on_write_datablock` when we do a copy on write, we only call `BKE_gpencil_data_update_orig_pointers` in `GPencilBackup::restore_to_gpencil` if a backup has been created. But `RuntimeBackup::init_from_id` returns early if `deg_copy_on_write_is_expanded` is false. Maybe the solution is to add some logic to `update_id_after_copy` to make sure the runtime orig pointers are updated.

Falk David commented

2022-03-07 13:12:53 +01:00

Added subscriber: @filedescriptor

Philipp Oeser commented

2022-03-07 13:54:20 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2022-03-07 13:54:20 +01:00

Cannot repro here.

**System Information**
Operating system: Linux-5.13.0-0.rc6.45.fc35.x86_64-x86_64-with-glibc2.34.9000 64 Bits
Graphics card: NVIDIA GeForce GTX 970M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 495.44
version: 3.2.0 Alpha, branch: master, commit date: 2022-03-07 06:49, hash: `rBad2948face07`

Cannot repro here. ``` **System Information** Operating system: Linux-5.13.0-0.rc6.45.fc35.x86_64-x86_64-with-glibc2.34.9000 64 Bits Graphics card: NVIDIA GeForce GTX 970M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 495.44 version: 3.2.0 Alpha, branch: master, commit date: 2022-03-07 06:49, hash: `rBad2948face07` ```

Pratik Borhade commented

2022-03-07 14:06:29 +01:00

Added subscriber: @PratikPB2123

Philipp Oeser commented

2022-03-07 15:02:36 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Philipp Oeser commented

2022-03-07 15:02:36 +01:00

Can confirm now, will bisect

Philipp Oeser commented

2022-03-07 15:36:41 +01:00

Caused by 7ca13eef7c

Caused by 7ca13eef7c

Falk David commented

2022-03-07 15:46:14 +01:00

Quick fix hack:

diff --git a/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc b/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc
index 6346bab1fe8..414f031ece4 100644
--- a/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc
+++ b/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc
@@ -41,6 +41,7 @@
 - include "DNA_ID.h"
 - include "DNA_anim_types.h"
 #include "DNA_armature_types.h"
+#include "DNA_gpencil_types.h"
 - include "DNA_mesh_types.h"
 - include "DNA_modifier_types.h"
 #include "DNA_object_types.h"
@@ -733,6 +734,14 @@ void update_id_after_copy(const Depsgraph *depsgraph,
       scene_setup_view_layers_after_remap(depsgraph, id_node, reinterpret_cast<Scene *>(id_cow));
       break;
     }
+    case ID_GD: {
+      bGPdata *gpd_cow = (bGPdata *)id_cow;
+      bGPDlayer *gpl = (bGPDlayer *)(gpd_cow->layers.first);
+      if (gpl != NULL && gpl->runtime.gpl_orig == NULL) {
+        BKE_gpencil_data_update_orig_pointers((bGPdata *)id_orig, gpd_cow);
+      }
+      break;
+    }
     default:
       break;
   }

Quick fix hack: ``` diff --git a/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc b/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc index 6346bab1fe8..414f031ece4 100644 --- a/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc +++ b/source/blender/depsgraph/intern/eval/deg_eval_copy_on_write.cc @@ -41,6 +41,7 @@ - include "DNA_ID.h" - include "DNA_anim_types.h" #include "DNA_armature_types.h" +#include "DNA_gpencil_types.h" - include "DNA_mesh_types.h" - include "DNA_modifier_types.h" #include "DNA_object_types.h" @@ -733,6 +734,14 @@ void update_id_after_copy(const Depsgraph *depsgraph, scene_setup_view_layers_after_remap(depsgraph, id_node, reinterpret_cast<Scene *>(id_cow)); break; } + case ID_GD: { + bGPdata *gpd_cow = (bGPdata *)id_cow; + bGPDlayer *gpl = (bGPDlayer *)(gpd_cow->layers.first); + if (gpl != NULL && gpl->runtime.gpl_orig == NULL) { + BKE_gpencil_data_update_orig_pointers((bGPdata *)id_orig, gpd_cow); + } + break; + } default: break; } ```

Sergey Sharybin commented

2022-03-08 09:36:17 +01:00

Added subscriber: @Sergey

Sergey Sharybin commented

2022-03-08 09:36:17 +01:00

If the datablock was not copied yet, there is nothing to be backed up from it. So this part of the logic seems to be working as intended.

@filedescriptor, your proposed patch looks good and safe.

If the datablock was not copied yet, there is nothing to be backed up from it. So this part of the logic seems to be working as intended. @filedescriptor, your proposed patch looks good and safe.

Falk David commented

2022-03-08 10:49:11 +01:00

Fixed by 21d633f83b but we might want to look into a cleaner solution.

Fixed by 21d633f83b but we might want to look into a cleaner solution.

Philipp Oeser commented

2022-03-08 11:19:05 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Philipp Oeser closed this issue

2022-03-08 11:19:05 +01:00

Philipp Oeser self-assigned this 2022-03-08 11:19:05 +01:00

Philipp Oeser commented

2022-03-08 11:19:05 +01:00

OK, will close then.

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GPencil: Crash when opening a file that has a gpencil data block with layer transforms #96216

Save the file and reopen it -> Blender crashes.

Open test file -> Blender crashes.