Assert that GIL is not held in blocking destructors (#57030)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57030
PR #57029 is not perfect; there are still obscure situations in which
we might allocate a shared_ptr to an RpcAgent that doesn't have a
no GIL constructor, so this PR adds the other half of the equation:
assert that we don't hold the GIL when running a blocking destructor.
This makes it possible to detect potential deadlocks even if the
code doesn't deadlock in practice (because you got lucky and none
of the threads you blocked on tried to also take out the GIL).
I considered whether or not to make this DEBUG_ONLY. For now it's
not, so I can get better CI coverage, and because this test only
happens in destructors of objects that die rarely.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Reviewed By: zou3519
Differential Revision: D28030582
Pulled By: ezyang
fbshipit-source-id: a7d7f6545223c4823c7f6036dfe29bd2edaf60a5
