erts: Fix race for process_flag(trap_exit,true)

and a concurrent exit signal.

We now actually guarantee that the process will not die
from exit signal *after* the call to process_flag(trap_exit,true)
has returned.

The race is narrow and probably quite hard to observe even if you
manage to provoke it. Has only been confirmed with the help of
return trace and a sleep in send_exit_signal().

Solution:
Seize status lock to prevent send_exit_signal() from reading
an old status (without TRAP_EXIT) and then writing PENDING_EXIT
after TRAP_EXIT has been set by process_flag_2().

0 files changed, 0 insertions, 0 deletions