Author mdk
Recipients ebarry, mdk, serhiy.storchaka, sjpalt
Date 2016-12-04.17:59:11
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Message-id <1480874352.19.0.0820696450314.issue28866@psf.upfronthosting.co.za>
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FWIW, in _PyType_Lookup I see the "300" PyLong being cached, and later, just before the segfault, I see its address getting out of the cache (a cache hit) but it's no longer a PyLong, it's scrambled, so we're getting a real pointer with scrambled values on the line:

    attribute = _PyType_Lookup(type, name);

segfaulting two lines later in:

    descrgetfunc local_get = Py_TYPE(attribute)->tp_descr_get

When I write scrambled value I mean: 

    (gdb) p *attribute                                                                                                         
    $21 = {_ob_next = 0xdbdbdbdbdbdbdbdb, _ob_prev = 0xdbdbdbdbdbdbdbdb, ob_refcnt = -2604246222170760229, ob_type = 0xdbdbdbd\
    bdbdbdbdb}                                                                                                                 

To debug interactive session in GDB I used:

    r -i weird.py < stdin

with "proxy.x" in the stdin file.
History
Date User Action Args
2016-12-04 17:59:12mdksetrecipients: + mdk, serhiy.storchaka, ebarry, sjpalt
2016-12-04 17:59:12mdksetmessageid: <1480874352.19.0.0820696450314.issue28866@psf.upfronthosting.co.za>
2016-12-04 17:59:12mdklinkissue28866 messages
2016-12-04 17:59:11mdkcreate