tree e11fb3068c6d06b8f3c28546db1626b02f464ad0
parent 9b1c003748d4df78416d50fce139f0875224440b
author Andrew G. Morgan <morgan@kernel.org> 1605153186 -0800
committer Andrew G. Morgan <morgan@kernel.org> 1605155483 -0800

Allow a dying thread to participate in the psx mechanism.

If a dying thread blocks all interrupts in order to die in peace,
it can deadlock the psx mechanism for all the surviving threads.
To account for this corner case, while waiting to enter the
_PSX_EXITING state, temporarily unblock the psx_tracker.psx_sig.

  https://github.com/golang/go/issues/42494

Add a psx_test.go:TestThreadChurn() test case for this issue.

Signed-off-by: Andrew G. Morgan <morgan@kernel.org>