forked from openkylin/python-greenlet
35 lines
1.1 KiB
ReStructuredText
35 lines
1.1 KiB
ReStructuredText
==========================
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Caveats and Known Issues
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==========================
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This document will describe known issues and sharp edges of greenlets.
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Native Functions Should Be Re-entrant
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=====================================
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Use caution when switching greenlet stacks that include native (C)
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frames. Much like with threads, if the library function is not
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re-entrant, and more than one greenlet attempts to enter it, subtle
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problems can result.
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Common constructs in C that may not be reentrant include:
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- static variables in functions;
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- global variables.
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This was the source of an issue in gevent that led to corruption of
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libuv's internal state. The fix was to avoid re-entering the
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vulnerable function.
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Use Caution Mixing Greenlets and Signal Handlers
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================================================
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In CPython, signal handler functions *must* return in order for the
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rest of the program to proceed. Switching greenlets in a signal
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handler to, for example, get back to the main greenlet, such that the
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signal handler function doesn't really return to CPython, is likely to
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lead to a hang.
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See :issue:`143` for an example.
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