Opened 6 years ago
Last modified 6 years ago
#29878 new Bug
GEOSContextHandle leaks probably due to thread local object destructing order
Reported by: | Yong Li | Owned by: | nobody |
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Component: | GIS | Version: | 1.11 |
Severity: | Normal | Keywords: | GEOS leak GIS |
Cc: | Sergey Fedoseev | Triage Stage: | Accepted |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
I have observed consistent GEOSContextHandle leaks when using Django Geometry features in temporary threads. And I can avoid the leaks by manually clearing all attributes of django.contrib.gis.geos.prototypes.io.thread_context
. My theory is that destructors of attributes in io.thread_context
call some GEOSFunc objects, and that can create new GEOSContextHandle while Python is clearing thread local storage.
- threadsafe.thread_context.handle is cleared
- io.thread_context attributes are cleared
- io.thread_context attributes are destructed, and then created new threadsafe.thread_context.handle.
When I am trying a minimized sample, I also found that it got double free or corruption error very often if I do GC in main thread right after the thread using GEOS is joined. So this may be another big issue
BTW, I am using Python 2.7.12 and django 1.11. But after checking the latest Django code, I think the issue is still there.
My sample code is:
Code highlighting:
#!/usr/bin/env python import gc import threading from django.contrib.gis.geos import GEOSGeometry _old_objs = None _new_objs = None _first_time = True def gc_objects(): gc.collect() objs_counts = {} for obj in gc.get_objects(): key = str(type(obj)) if key in objs_counts: objs_counts[key] += 1 else: objs_counts[key] = 1 return objs_counts def dump_memory_leaks(): global _old_objs global _new_objs global _first_time if _first_time: _old_objs = gc_objects() _first_time = False else: _new_objs = gc_objects() leaked = {} for k, v in _new_objs.items(): old_v = _old_objs.get(k) if old_v: diff = _new_objs[k] - old_v if diff > 0: leaked[str(k)] = diff else: leaked[str(k)] = v print("Leaks: {}".format(leaked)) _new_objs = None def use_geos(): GEOSGeometry('POINT(5 23)') # These lines can get rid of the GEOSContextHandle leak # from django.contrib.gis.geos.prototypes.io import thread_context as io_thread_context # io_thread_context.__dict__.clear() dump_memory_leaks() if __name__ == '__main__': for i in range(10): t = threading.Thread(target=use_geos) t.start() t.join() # If I do GC here, it will crash with "double free or corruption" at random `i` # dump_memory_leaks()
Output:
Leaks: {"<type 'dict'>": 2, "<class 'django.contrib.gis.geos.prototypes.threadsafe.GEOSContextHandle'>": 1, "<type 'weakref'>": 1, "<class 'django.contrib.gis.geos.libgeos.LP_GEOSContextHandle_t'>": 1, "<type 'frame'>": 1} Leaks: {"<type 'weakref'>": 2, "<class 'django.contrib.gis.geos.prototypes.threadsafe.GEOSContextHandle'>": 2, "<class 'django.contrib.gis.geos.libgeos.LP_GEOSContextHandle_t'>": 2, "<type 'dict'>": 4} Leaks: {"<type 'weakref'>": 3, "<class 'django.contrib.gis.geos.prototypes.threadsafe.GEOSContextHandle'>": 3, "<class 'django.contrib.gis.geos.libgeos.LP_GEOSContextHandle_t'>": 3, "<type 'dict'>": 6} Leaks: {"<type 'weakref'>": 4, "<class 'django.contrib.gis.geos.prototypes.threadsafe.GEOSContextHandle'>": 4, "<class 'django.contrib.gis.geos.libgeos.LP_GEOSContextHandle_t'>": 4, "<type 'dict'>": 8} Leaks: {"<type 'frame'>": 1, "<type 'weakref'>": 5, "<type 'instancemethod'>": 1, "<class 'django.contrib.gis.geos.libgeos.LP_GEOSContextHandle_t'>": 5, "<class 'django.contrib.gis.geos.prototypes.threadsafe.GEOSContextHandle'>": 5, "<type 'dict'>": 10} Leaks: {"<type 'weakref'>": 6, "<class 'django.contrib.gis.geos.prototypes.threadsafe.GEOSContextHandle'>": 6, "<class 'django.contrib.gis.geos.libgeos.LP_GEOSContextHandle_t'>": 6, "<type 'dict'>": 12} Leaks: {"<type 'weakref'>": 7, "<class 'django.contrib.gis.geos.prototypes.threadsafe.GEOSContextHandle'>": 7, "<class 'django.contrib.gis.geos.libgeos.LP_GEOSContextHandle_t'>": 7, "<type 'dict'>": 14} Leaks: {"<type 'weakref'>": 8, "<class 'django.contrib.gis.geos.prototypes.threadsafe.GEOSContextHandle'>": 8, "<class 'django.contrib.gis.geos.libgeos.LP_GEOSContextHandle_t'>": 8, "<type 'dict'>": 16} Leaks: {"<type 'weakref'>": 9, "<class 'django.contrib.gis.geos.prototypes.threadsafe.GEOSContextHandle'>": 9, "<class 'django.contrib.gis.geos.libgeos.LP_GEOSContextHandle_t'>": 9, "<type 'dict'>": 18}
Change History (7)
comment:1 by , 6 years ago
Description: | modified (diff) |
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comment:2 by , 6 years ago
Description: | modified (diff) |
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comment:3 by , 6 years ago
Description: | modified (diff) |
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comment:4 by , 6 years ago
Type: | Uncategorized → Bug |
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comment:5 by , 6 years ago
Cc: | added |
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follow-up: 7 comment:6 by , 6 years ago
Description: | modified (diff) |
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Triage Stage: | Unreviewed → Accepted |
comment:7 by , 6 years ago
Thanks!
Replying to Tim Graham:
Tentatively accepting. I'm not a GeoDjango expert. I updated the ticket description to make the script compatible with Python 3 as Python 2 is no longer supported as of Django 2.0.
Tentatively accepting. I'm not a GeoDjango expert. I updated the ticket description to make the script compatible with Python 3 as Python 2 is no longer supported as of Django 2.0.