Commit 6c25413183 added the flag ZEND_JIT_EXIT_INVALIDATE which
resets the trace handlers in zend_jit_trace_exit(), but forgot to
lock the shared memory section.
This could cause another worker process who still saw the
ZEND_JIT_TRACE_JITED flag to schedule ZEND_JIT_TRACE_STOP_LINK, but
when it arrived at the ZEND_JIT_DEBUG_TRACE_STOP, the handler was
already reverted by the first worker process and thus
zend_jit_find_trace() fails.
This in turn generated a bogus jump offset in the JITed code, crashing
the PHP process.
e217138b40