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athrpf
n00b
Joined: 13 Jun 2012
Posts: 1
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 Posted: Wed Jun 13, 2012 7:42 am Post subject: valgrind and python |
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Hi everyone,
I am trying to debug a c++ library that is called from python code (written using boost::python). Valgrind itself works fine for pure c++ programs (after lots of trouble with strlen). However, if I do
| Code: | | valgrind python myscript.py |
where myscript.py calls the C++ code, valgrind does nothing at all and just lets the program segfault - after the
| Code: | | *** glibc detected *** /usr/bin/python2.7: free(): invalid next size (fast): 0x00000000011640c0 *** |
there is no output from valgrind.
I tried this on ubuntu, and there it works without problems - memory errors that are raised in the c++ code are caught by valgrind.
Any help would be much appreciated |
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aharel
n00b
Joined: 16 Nov 2011
Posts: 36
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| Posted: Sun May 05, 2013 7:07 pm Post subject: |
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Found this old thread with google. So for the next person to stumble here, the natural thing to try is to add the flags
| Code: | | --trace-children=yes |
to the valgrind command line |
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Hu
Moderator
Joined: 06 Mar 2007
Posts: 21586
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| Posted: Sun May 05, 2013 9:35 pm Post subject: |
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| The OP specified nothing about the Python program creating children, so that is likely not the problem. Python defaults to using a custom memory allocator that routinely accesses memory in ways disallowed by normal memory safety rules, causing numerous warnings from Valgrind. Compile Python with the flag --without-pymalloc to switch it to the standard allocator, which does not routinely access free memory. Some versions of Python also support --with-valgrind, which will attempt to auto-detect Valgrind and switch off PyMalloc only when Valgrind is present. |
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