Function ktr_enqueuerequest

freebsd/kern/kern_ktrace.c:343–353

* Some trace generation environments don't permit direct access to VFS, * such as during a context switch where sleeping is not allowed. Under these * circumstances, queue a request to the thread to be written asynchronously * later. */

 * later.
 */
static void
ktr_enqueuerequest(struct thread *td, struct ktr_request *req)
{

	mtx_lock(&ktrace_mtx);
	STAILQ_INSERT_TAIL(&td->td_proc->p_ktr, req, ktr_list);
	mtx_unlock(&ktrace_mtx);
	thread_lock(td);
	td->td_flags |= TDF_ASTPENDING;
	thread_unlock(td);
}

/*
 * Drain any pending ktrace records from the per-thread queue to disk.  This