rcu: Eliminate BUG_ON() for kernel/rcu/tree.c (08543bda) · Commits · 戴 / test

The tree.c file has a number of calls to BUG_ON(), which panics the kernel, which is not a good strategy for devices (like embedded) that don't have a way to capture console output. This commit therefore converts these BUG_ON() calls to WARN_ON_ONCE() and WARN_ONCE(). Reported-by:

Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:

Paul E. McKenney <paulmck@linux.ibm.com>

kernel/rcu/tree.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -2826,7 +2826,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func, int cpu, bool lazy)
		* Very early boot, before rcu_init(). Initialize if needed
		* and then drop through to queue the callback.
		*/
		BUG_ON(cpu != -1);
		WARN_ON_ONCE(cpu != -1);
		WARN_ON_ONCE(!rcu_is_watching());
		if (rcu_segcblist_empty(&rdp->cblist))
		rcu_segcblist_init(&rdp->cblist);
		@@ -3485,7 +3485,8 @@ static int __init rcu_spawn_gp_kthread(void)

		rcu_scheduler_fully_active = 1;
		t = kthread_create(rcu_gp_kthread, NULL, "%s", rcu_state.name);
		BUG_ON(IS_ERR(t));
		if (WARN_ONCE(IS_ERR(t), "%s: Could not start grace-period kthread, OOM is now expected behavior\n", __func__))
		return 0;
		rnp = rcu_get_root();
		raw_spin_lock_irqsave_rcu_node(rnp, flags);
		rcu_state.gp_kthread = t;

Admin message