Segfault printing depsgraph items #70481

New Issue

Paul Melis · 2019-10-03T16:39:00+02:00

Paul Melis commented

2019-10-03 16:39:00 +02:00

System Information
Operating system: Arch Linux
Graphics card: GTX Titan

Blender Version
Broken: 2.81.13 (a6ad80d9e8)

Short description of error

Segfault:

# Blender 2.81 (sub 13), Commit date: 2019-10-03 13:36, Hash a6ad80d9e852

# backtrace
/home/paulm/software/blender-debug-git/blender(BLI_system_backtrace+0x35) [0x56414497511c]
/home/paulm/software/blender-debug-git/blender(+0x27711c3) [0x5641445cc1c3]
/home/paulm/software/blender-debug-git/blender(+0x27713c2) [0x5641445cc3c2]
/usr/lib/libc.so.6(+0x3a7e0) [0x7f8196c037e0]
/usr/lib/libc.so.6(+0x15ec87) [0x7f8196d27c87]
/usr/lib/libpython3.7m.so.1.0(PyUnicode_FromString+0xa) [0x7f819f3b95da]
/home/paulm/software/blender-debug-git/blender(+0x2bd8dc7) [0x564144a33dc7]
/usr/lib/libpython3.7m.so.1.0(PyObject_Repr+0x506) [0x7f819f3e5796]
/usr/lib/libpython3.7m.so.1.0(+0x16a009) [0x7f819f41f009]
/usr/lib/libpython3.7m.so.1.0(PyObject_Str+0x70) [0x7f819f3e5bd0]
/usr/lib/libpython3.7m.so.1.0(PyFile_WriteObject+0x3f) [0x7f819f46ebff]
/usr/lib/libpython3.7m.so.1.0(+0x1d229e) [0x7f819f48729e]
/usr/lib/libpython3.7m.so.1.0(_PyMethodDef_RawFastCallKeywords+0xf8) [0x7f819f3bb478]
/usr/lib/libpython3.7m.so.1.0(_PyCFunction_FastCallKeywords+0x24) [0x7f819f3bb714]
/usr/lib/libpython3.7m.so.1.0(+0x1382ec) [0x7f819f3ed2ec]
/usr/lib/libpython3.7m.so.1.0(_PyEval_EvalFrameDefault+0xaa7) [0x7f819f422ed7]
/usr/lib/libpython3.7m.so.1.0(_PyEval_EvalCodeWithName+0x2f8) [0x7f819f3db768]
/usr/lib/libpython3.7m.so.1.0(PyEval_EvalCodeEx+0x3a) [0x7f819f3dc52a]
/usr/lib/libpython3.7m.so.1.0(PyEval_EvalCode+0x1c) [0x7f819f46c09c]
/usr/lib/libpython3.7m.so.1.0(+0x1fb815) [0x7f819f4b0815]
/usr/lib/libpython3.7m.so.1.0(PyRun_StringFlags+0x80) [0x7f819f4b08c0]
/home/paulm/software/blender-debug-git/blender(BPY_execute_string_ex+0x15f) [0x564144a31228]
/home/paulm/software/blender-debug-git/blender(+0x276f8e8) [0x5641445ca8e8]
/home/paulm/software/blender-debug-git/blender(BLI_argsParse+0xf1) [0x5641449022cb]
/home/paulm/software/blender-debug-git/blender(main_args_setup_post+0x2f) [0x5641445cc0fd]
/home/paulm/software/blender-debug-git/blender(main+0x431) [0x5641445c7896]
/usr/lib/libc.so.6(__libc_start_main+0xf3) [0x7f8196befee3]
/home/paulm/software/blender-debug-git/blender(_start+0x2e) [0x5641445c72ee]

Exact steps for others to reproduce the error

blender -b --python-expr 'import bpy; d=bpy.context.evaluated_depsgraph_get(); print(len(d.ids)); l=list(d.ids); print(l)'

Without the final print() all is well.

**System Information** Operating system: Arch Linux Graphics card: GTX Titan **Blender Version** Broken: 2.81.13 (a6ad80d9e852) **Short description of error** Segfault: ``` # Blender 2.81 (sub 13), Commit date: 2019-10-03 13:36, Hash a6ad80d9e852 # backtrace /home/paulm/software/blender-debug-git/blender(BLI_system_backtrace+0x35) [0x56414497511c] /home/paulm/software/blender-debug-git/blender(+0x27711c3) [0x5641445cc1c3] /home/paulm/software/blender-debug-git/blender(+0x27713c2) [0x5641445cc3c2] /usr/lib/libc.so.6(+0x3a7e0) [0x7f8196c037e0] /usr/lib/libc.so.6(+0x15ec87) [0x7f8196d27c87] /usr/lib/libpython3.7m.so.1.0(PyUnicode_FromString+0xa) [0x7f819f3b95da] /home/paulm/software/blender-debug-git/blender(+0x2bd8dc7) [0x564144a33dc7] /usr/lib/libpython3.7m.so.1.0(PyObject_Repr+0x506) [0x7f819f3e5796] /usr/lib/libpython3.7m.so.1.0(+0x16a009) [0x7f819f41f009] /usr/lib/libpython3.7m.so.1.0(PyObject_Str+0x70) [0x7f819f3e5bd0] /usr/lib/libpython3.7m.so.1.0(PyFile_WriteObject+0x3f) [0x7f819f46ebff] /usr/lib/libpython3.7m.so.1.0(+0x1d229e) [0x7f819f48729e] /usr/lib/libpython3.7m.so.1.0(_PyMethodDef_RawFastCallKeywords+0xf8) [0x7f819f3bb478] /usr/lib/libpython3.7m.so.1.0(_PyCFunction_FastCallKeywords+0x24) [0x7f819f3bb714] /usr/lib/libpython3.7m.so.1.0(+0x1382ec) [0x7f819f3ed2ec] /usr/lib/libpython3.7m.so.1.0(_PyEval_EvalFrameDefault+0xaa7) [0x7f819f422ed7] /usr/lib/libpython3.7m.so.1.0(_PyEval_EvalCodeWithName+0x2f8) [0x7f819f3db768] /usr/lib/libpython3.7m.so.1.0(PyEval_EvalCodeEx+0x3a) [0x7f819f3dc52a] /usr/lib/libpython3.7m.so.1.0(PyEval_EvalCode+0x1c) [0x7f819f46c09c] /usr/lib/libpython3.7m.so.1.0(+0x1fb815) [0x7f819f4b0815] /usr/lib/libpython3.7m.so.1.0(PyRun_StringFlags+0x80) [0x7f819f4b08c0] /home/paulm/software/blender-debug-git/blender(BPY_execute_string_ex+0x15f) [0x564144a31228] /home/paulm/software/blender-debug-git/blender(+0x276f8e8) [0x5641445ca8e8] /home/paulm/software/blender-debug-git/blender(BLI_argsParse+0xf1) [0x5641449022cb] /home/paulm/software/blender-debug-git/blender(main_args_setup_post+0x2f) [0x5641445cc0fd] /home/paulm/software/blender-debug-git/blender(main+0x431) [0x5641445c7896] /usr/lib/libc.so.6(__libc_start_main+0xf3) [0x7f8196befee3] /home/paulm/software/blender-debug-git/blender(_start+0x2e) [0x5641445c72ee] ``` **Exact steps for others to reproduce the error** ``` blender -b --python-expr 'import bpy; d=bpy.context.evaluated_depsgraph_get(); print(len(d.ids)); l=list(d.ids); print(l)' ``` Without the final `print()` all is well.

Paul Melis commented

2019-10-03 16:39:00 +02:00

Added subscriber: @PaulMelis

Paul Melis commented

2019-10-03 16:52:28 +02:00

Hmmm, https://docs.blender.org/api/blender2.8/bpy.types.Depsgraph.html#bpy.types.Depsgraph.object_instances shows a warning for depsgraph.object_instances to "only use this as an iterator, never as a sequence, and do not keep any references to its items", but that warning is missing for depsgraph.ids. I guess the same applies?

The segfault is still nasty, though.

Hmmm, https://docs.blender.org/api/blender2.8/bpy.types.Depsgraph.html#bpy.types.Depsgraph.object_instances shows a warning for `depsgraph.object_instances` to "only use this as an iterator, never as a sequence, and do not keep any references to its items", but that warning is missing for `depsgraph.ids`. I guess the same applies? The segfault is still nasty, though.

Bastien Montagne commented

2019-10-03 20:43:17 +02:00

Added subscriber: @mont29

Bastien Montagne commented

2019-10-03 20:43:17 +02:00

Changed status from 'Open' to: 'Archived'

Bastien Montagne closed this issue

2019-10-03 20:43:17 +02:00

Bastien Montagne self-assigned this 2019-10-03 20:43:17 +02:00

Bastien Montagne commented

2019-10-03 20:43:17 +02:00

Look like you found the answer by yourself reading the doc… Segfault is impossible to avoid here, not without a tremendous impact on performances.

Bastien Montagne commented

2019-10-03 20:56:39 +02:00

Changed status from 'Archived' to: 'Open'

Bastien Montagne reopened this issue

2019-10-03 20:56:39 +02:00

Bastien Montagne commented

2019-10-03 20:56:39 +02:00

Hrmmmm… Read your comment too quickly actually.

Don’t think this should crash, object_instances is a specific case, the other iterators should point to some (very slightly) more permanent memory. So you should not store them for any 'long' time, but keeping them in a list should be possible, until the next DEG update is run.

Tried here on linux with a debug build with ASAN enabled, and got no crash nor any error reported, it works just fine.

Does that command also crash for you?

blender -t 1 -b --python-expr 'import bpy; d=bpy.context.evaluated_depsgraph_get(); print(len(d.ids)); l=list(d.ids); print(l)'

Hrmmmm… Read your comment too quickly actually. Don’t think this should crash, `object_instances` is a specific case, the other iterators should point to some (very slightly) more permanent memory. So you should not store them for any 'long' time, but keeping them in a list should be possible, until the next DEG update is run. Tried here on linux with a debug build with ASAN enabled, and got no crash nor any error reported, it works just fine. Does that command also crash for you? ``` blender -t 1 -b --python-expr 'import bpy; d=bpy.context.evaluated_depsgraph_get(); print(len(d.ids)); l=list(d.ids); print(l)'

Bastien Montagne commented

2019-10-03 21:03:55 +02:00

Should go to bed… was trying with 2.80 release, not my debug build of master… xD

Bastien Montagne commented

2019-10-03 21:07:53 +02:00

Crash happen when trying to display the evaluated version of the master collection, the 9th item of the list. This works fine for me:

blender -b --python-expr 'import bpy; d=bpy.context.evaluated_depsgraph_get(); print(len(d.ids)); l=list(d.ids); print(l[:8], l[9:])'

Crash happen when trying to display the evaluated version of the master collection, the 9th item of the list. This works fine for me: ``` blender -b --python-expr 'import bpy; d=bpy.context.evaluated_depsgraph_get(); print(len(d.ids)); l=list(d.ids); print(l[:8], l[9:])'

blender-admin commented

2019-10-04 12:24:26 +02:00

This issue was referenced by 19b0f69009

This issue was referenced by 19b0f69009501df8b153d33ffcf6977019d53291

Bastien Montagne commented

2019-10-04 12:27:39 +02:00

Changed status from 'Open' to: 'Resolved'

Bastien Montagne closed this issue

2019-10-04 12:27:39 +02:00

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Segfault printing depsgraph items #70481