gh-120321: Make gi_frame_state transitions atomic in FT build #142599
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This makes generator frame state transitions atomic in the free threading build, which avoids segfaults when trying to execute a generator from multiple threads concurrently. There are still a few operations that aren't thread-safe and may crash if performed concurrently on the same generator/coroutine: * Accessing gi_yieldfrom/cr_await/ag_await * Accessing gi_frame/cr_frame/ag_frame * Async generator operations
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🤖 New build scheduled with the buildbot fleet by @colesbury for commit ac3974d 🤖 Results will be shown at: https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F142599%2Fmerge If you want to schedule another build, you need to add the 🔨 test-with-refleak-buildbots label again. |
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| FT_ATOMIC_STORE_INT8_RELEASE(gen->gi_frame_state, FRAME_SUSPENDED + oparg); | ||
| #ifdef Py_GIL_DISABLED | ||
| ((_PyThreadStateImpl *)tstate)->gen_last_frame_state = FRAME_SUSPENDED + oparg; | ||
| #endif |
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Would it make sense to factor this out into a helper function? It's duplicated in ceval.c. Also, having helper to update both would reduce the chance that we update one without the other.
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| if (gen->gi_frame_state < FRAME_EXECUTING) { | ||
| gen->gi_frame_state = FRAME_EXECUTING; |
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Do these loads need to use atomics (in the FT build)?
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This makes generator frame state transitions atomic in the free threading build, which avoids segfaults when trying to execute a generator from multiple threads concurrently.
There are still a few operations that aren't thread-safe and may crash if performed concurrently on the same generator/coroutine: