Sculpting Crash When Dyntopo Enabled With Tiling Settings Enabled #57988

New Issue

Eoin O'Neill · 2018-11-21T23:35:00+01:00

Eoin O'Neill commented

2018-11-21 23:35:00 +01:00

System Information
Ubuntu 18.04 bionic (Linux 4.15.0-39-generic)
Gnome Shell
CPU: Intel Core i7-4770K
GPU: GeForce GTX 760
RAM: 11946MiB

Blender Version
Broken: blender2.8 , a9bf6a3b3a

Short description of error
Blender will crash when working in dyntopo when tiling on x y or z is enabled. The crash seems to be caused by an uninitialized bounding box pointer inside the Object structure. Backtrace will be provided below.

Exact steps for others to reproduce the error

Create a new blend file, use default cube or create a new cube or plane.
Click on the sculpt workspace
Click on dyntopo and enable with any setting (tested using relative detail)
Click on Symmetry/Lock and toggle X, Y, or Z tiling settings. Any offset should work.
Crash will occur immediately when trying to sculpt on surface.

Here's a backtrace with some relevant information.

Thread 1 "blender" received signal SIGSEGV, Segmentation fault.
0x000055555768d87d in do_tiled (sd=0x7fffc78f6d88, ob=0x7fffcd98be08, brush=0x7fffc6909608, ups=0x7fffc793fff8, 
    action=0x55555768b38e <sculpt_topology_update>)
    at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/sculpt.c:3972
3972				start[dim] = (bbMin[dim] - orgLoc[dim] - radius) / step[dim];
(gdb) bt
- 0  0x000055555768d87d in do_tiled (sd=0x7fffc78f6d88, ob=0x7fffcd98be08, brush=0x7fffc6909608, ups=0x7fffc793fff8, action=0x55555768b38e <sculpt_topology_update>) at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/sculpt.c:3972
- 1  0x000055555768ddb9 in do_symmetrical_brush_actions (sd=0x7fffc78f6d88, ob=0x7fffcd98be08, action=0x55555768b38e <sculpt_topology_update>, ups=0x7fffc793fff8) at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/sculpt.c:4055
#2  0x0000555557690a6d in sculpt_stroke_update_step (C=0x7fffcdf1ca08, UNUSED_stroke=0x7fffb1fc5008, itemptr=0x7fffffffd590)
    at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/sculpt.c:4981
#3  0x0000555557659bad in paint_brush_stroke_add_step (C=0x7fffcdf1ca08, op=0x7fffa8794688, mouse_in=0x7fffffffd64c, pressure=1)
    at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/paint_stroke.c:555
#4  0x000055555765bfb9 in paint_stroke_modal (C=0x7fffcdf1ca08, op=0x7fffa8794688, event=0x7fffae7ef088)
    at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/paint_stroke.c:1302
#5  0x0000555557690f25 in sculpt_brush_stroke_invoke (C=0x7fffcdf1ca08, op=0x7fffa8794688, event=0x7fffae7ef088)
    at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/sculpt.c:5104
#6  0x000055555700d2ea in wm_operator_invoke (C=0x7fffcdf1ca08, ot=0x7fffc7a77108, event=0x7fffae7ef088, properties=0x7fffb1cc5908, reports=0x0, poll_only=false, use_last_properties=true)
    at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wm_event_system.c:1323
#7  0x000055555700ef94 in wm_handler_operator_call (C=0x7fffcdf1ca08, handlers=0x7fffc68dfa18, handler=0x7fffc694f288, event=0x7fffae7ef088, properties=0x7fffb1cc5908)
    at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wm_event_system.c:2041
#8  0x000055555700fa75 in wm_handlers_do_intern (C=0x7fffcdf1ca08, event=0x7fffae7ef088, handlers=0x7fffc68dfa18)
    at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wm_event_system.c:2343
#9  0x00005555570106f6 in wm_handlers_do (C=0x7fffcdf1ca08, event=0x7fffae7ef088, handlers=0x7fffc68dfa18)
    at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wm_event_system.c:2603
#10 0x0000555557011de6 in wm_event_do_handlers (C=0x7fffcdf1ca08)
    at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wm_event_system.c:3074
#11 0x00005555570065cb in WM_main (C=0x7fffcdf1ca08)
---Type <return> to continue, or q <return> to quit---q
 at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wQuit

My attempts to try to fix this on my own were in vain. However, I found that the problem is likely due to an invalid pointer to the object's bounding box:

(gdb) p /s *ob->bb
Cannot access memory at address 0x0

bbMin and bbMax are thus invalid pointers and cannot be used in the following line:

start[dim] = (bbMin[dim] - orgLoc[dim] - radius) / step[dim];

I would suggest checking that dyntopo is accurately creating and initializing bounding box data -- however, I'm not sure since I'm not familiar with the codebase.

**System Information** Ubuntu 18.04 bionic (Linux 4.15.0-39-generic) Gnome Shell CPU: Intel Core i7-4770K GPU: GeForce GTX 760 RAM: 11946MiB **Blender Version** Broken: blender2.8 , a9bf6a3b3ad **Short description of error** Blender will crash when working in dyntopo when tiling on x y or z is enabled. The crash seems to be caused by an uninitialized bounding box pointer inside the Object structure. Backtrace will be provided below. **Exact steps for others to reproduce the error** - Create a new blend file, use default cube or create a new cube or plane. - Click on the `sculpt` workspace - Click on `dyntopo` and enable with any setting (tested using relative detail) - Click on `Symmetry/Lock` and toggle X, Y, or Z tiling settings. Any offset should work. - Crash will occur immediately when trying to sculpt on surface. Here's a backtrace with some relevant information. ``` Thread 1 "blender" received signal SIGSEGV, Segmentation fault. 0x000055555768d87d in do_tiled (sd=0x7fffc78f6d88, ob=0x7fffcd98be08, brush=0x7fffc6909608, ups=0x7fffc793fff8, action=0x55555768b38e <sculpt_topology_update>) at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/sculpt.c:3972 3972 start[dim] = (bbMin[dim] - orgLoc[dim] - radius) / step[dim]; (gdb) bt - 0 0x000055555768d87d in do_tiled (sd=0x7fffc78f6d88, ob=0x7fffcd98be08, brush=0x7fffc6909608, ups=0x7fffc793fff8, action=0x55555768b38e <sculpt_topology_update>) at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/sculpt.c:3972 - 1 0x000055555768ddb9 in do_symmetrical_brush_actions (sd=0x7fffc78f6d88, ob=0x7fffcd98be08, action=0x55555768b38e <sculpt_topology_update>, ups=0x7fffc793fff8) at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/sculpt.c:4055 #2 0x0000555557690a6d in sculpt_stroke_update_step (C=0x7fffcdf1ca08, UNUSED_stroke=0x7fffb1fc5008, itemptr=0x7fffffffd590) at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/sculpt.c:4981 #3 0x0000555557659bad in paint_brush_stroke_add_step (C=0x7fffcdf1ca08, op=0x7fffa8794688, mouse_in=0x7fffffffd64c, pressure=1) at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/paint_stroke.c:555 #4 0x000055555765bfb9 in paint_stroke_modal (C=0x7fffcdf1ca08, op=0x7fffa8794688, event=0x7fffae7ef088) at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/paint_stroke.c:1302 #5 0x0000555557690f25 in sculpt_brush_stroke_invoke (C=0x7fffcdf1ca08, op=0x7fffa8794688, event=0x7fffae7ef088) at /home/eoin/Source/blender/blender-git/source/blender/editors/sculpt_paint/sculpt.c:5104 #6 0x000055555700d2ea in wm_operator_invoke (C=0x7fffcdf1ca08, ot=0x7fffc7a77108, event=0x7fffae7ef088, properties=0x7fffb1cc5908, reports=0x0, poll_only=false, use_last_properties=true) at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wm_event_system.c:1323 #7 0x000055555700ef94 in wm_handler_operator_call (C=0x7fffcdf1ca08, handlers=0x7fffc68dfa18, handler=0x7fffc694f288, event=0x7fffae7ef088, properties=0x7fffb1cc5908) at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wm_event_system.c:2041 #8 0x000055555700fa75 in wm_handlers_do_intern (C=0x7fffcdf1ca08, event=0x7fffae7ef088, handlers=0x7fffc68dfa18) at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wm_event_system.c:2343 #9 0x00005555570106f6 in wm_handlers_do (C=0x7fffcdf1ca08, event=0x7fffae7ef088, handlers=0x7fffc68dfa18) at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wm_event_system.c:2603 #10 0x0000555557011de6 in wm_event_do_handlers (C=0x7fffcdf1ca08) at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wm_event_system.c:3074 #11 0x00005555570065cb in WM_main (C=0x7fffcdf1ca08) ---Type <return> to continue, or q <return> to quit---q at /home/eoin/Source/blender/blender-git/source/blender/windowmanager/intern/wQuit ``` My attempts to try to fix this on my own were in vain. However, I found that the problem is likely due to an invalid pointer to the object's bounding box: ``` (gdb) p /s *ob->bb Cannot access memory at address 0x0 ``` `bbMin` and `bbMax` are thus invalid pointers and cannot be used in the following line: ``` start[dim] = (bbMin[dim] - orgLoc[dim] - radius) / step[dim]; ``` I would suggest checking that dyntopo is accurately creating and initializing bounding box data -- however, I'm not sure since I'm not familiar with the codebase.

Eoin O'Neill commented

2018-11-21 23:35:00 +01:00

Added subscriber: @eoinoneill