Re: Large memory usage by gdb

On 2017-08-07 23:04, Alex Lindsay wrote:
> Yes, I've also seen all those errors. I wrote them off to errors in
> the python library but maybe I should have looked more closely
> 
> On 08/07/2017 02:53 PM, Philippe Waroquiers wrote:
>> On Mon, 2017-08-07 at 10:14 +0100, Yao Qi wrote:
>> 
>>> leaks are bugs, and we should fix them.  I can find these leaks in
>>> valgrind too,
>> When running valgrind + gdb on a small program, I also get
>> many errors like the below (GDB 8.0, Debian 8).
>> 
>> Do you also see that ?
>> 
>> 
>> Philippe
>> 
>> ==9360== Invalid read of size 4
>> ==9360==    at 0x58AD9F3: PyObject_Free (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x4C5E7F: gdb_Py_DECREF (python-internal.h:194)
>> ==9360==    by 0x4C5E7F: decref (py-ref.h:36)
>> ==9360==    by 0x4C5E7F: ~ref_ptr (gdb_ref_ptr.h:91)
>> ==9360==    by 0x4C5E7F: unicode_to_encoded_string(_object*, char 
>> const*) (py-utils.c:74)
>> ==9360==    by 0x4C5F9C: python_string_to_host_string(_object*) 
>> (py-utils.c:158)
>> ==9360==    by 0x4BBDDD: get_doc_string(_object*, _object*) 
>> (py-param.c:314)
>> ==9360==    by 0x4BC11D: parmpy_init(_object*, _object*, _object*) 
>> (py-param.c:707)
>> ==9360==    by 0x580AD5B: ??? (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x5899BE2: PyObject_Call (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x58CD441: PyEval_EvalFrameEx (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x594218F: PyEval_EvalCodeEx (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x589132B: ??? (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x5899BE2: PyObject_Call (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x58DC0E4: ??? (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==  Address 0x6f0c020 is 1,280 bytes inside a block of size 
>> 3,133 free'd
>> ==9360==    at 0x4C29B8A: realloc (vg_replace_malloc.c:785)
>> ==9360==    by 0x5862625: _PyString_Resize (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x57E40AC: PyUnicodeUCS4_EncodeUTF8 (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x5848A98: ??? (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x5899BE2: PyObject_Call (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x59416E6: PyEval_CallObjectWithKeywords (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x5906C4D: PyCodec_Encode (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x57E4AB4: PyUnicodeUCS4_AsEncodedString (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x4C5E44: unicode_to_encoded_string(_object*, char 
>> const*) (py-utils.c:74)
>> ==9360==    by 0x4C5F9C: python_string_to_host_string(_object*) 
>> (py-utils.c:158)
>> ==9360==    by 0x4BBDDD: get_doc_string(_object*, _object*) 
>> (py-param.c:314)
>> ==9360==    by 0x4BC11D: parmpy_init(_object*, _object*, _object*) 
>> (py-param.c:707)
>> ==9360==  Block was alloc'd at
>> ==9360==    at 0x4C27BF5: malloc (vg_replace_malloc.c:299)
>> ==9360==    by 0x5864249: PyString_FromStringAndSize (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x57E41C6: PyUnicodeUCS4_EncodeUTF8 (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x5848A98: ??? (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x5899BE2: PyObject_Call (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x59416E6: PyEval_CallObjectWithKeywords (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x5906C4D: PyCodec_Encode (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x57E4AB4: PyUnicodeUCS4_AsEncodedString (in 
>> /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0)
>> ==9360==    by 0x4C5E44: unicode_to_encoded_string(_object*, char 
>> const*) (py-utils.c:74)
>> ==9360==    by 0x4C5F9C: python_string_to_host_string(_object*) 
>> (py-utils.c:158)
>> ==9360==    by 0x4BBDDD: get_doc_string(_object*, _object*) 
>> (py-param.c:314)
>> ==9360==    by 0x4BC11D: parmpy_init(_object*, _object*, _object*) 
>> (py-param.c:707)
>> 
>> 

This is expected with Python:

https://svn.python.org/projects/python/trunk/Misc/README.valgrind

Simon