Yes, this is hard, that's why I'm here :) I've enabled the equivalent tools to valgrind in Visual Studio, and tried setting PYTHONMALLOC=debug, but neither of those seem to be showing anything either. I don't really know what else to try in this direction.
/Geoff On Sat, Oct 5, 2019 at 7:22 AM dieter <die...@handshake.de> wrote: > Geoff Bache <geoff.ba...@gmail.com> writes: > > ... > > We are running Python embedded in our C++ product and are now > experiencing > > crashes (access violation reading 0xffffffffff on Windows) in the Python > > garbage collector. > > Errors like this are very difficult to analyse. The main reason: > the memory corruption is likely far away from the point when > it is finally detected (by an access violation in your case). > > Python can be built in a special way to add marks to > its allocated memory blocks and verify their validity. > This increases the chance to detect a memory corruption earlier > and thereby facilitates the detection of the root cause. > > There are tools for the analysis of memory management problems > (e.g. "valgrind", though this may be for Linux). In my > experience, even with those tools, the analysis is very difficult. > > I have several times successfully analysed memory corruption > problems. In those cases, I have been lucky that the corruption > was reproducible and affected typically the same address. > Thus, I could put a (hardware) memory breakpoint at this address > stopping the program as soon as this address was written and > then analyse the state in the debugger. This way, I could detect > precisely which code caused the corruption. However, > this was quite a long time ago; nowadays, modern operating systems > employ address randomization thus reducing significantly that > the corruption affects the same address (which may mean that > you need to deactivate address randomization to get a better chance > for this kind of analysis. > > -- > https://mail.python.org/mailman/listinfo/python-list > -- https://mail.python.org/mailman/listinfo/python-list
