Commit-ID: 08543bda42ef06c5ee4cd74501c894aa7cc13ea8 Gitweb: https://git.kernel.org/tip/08543bda42ef06c5ee4cd74501c894aa7cc13ea8 Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxx> AuthorDate: Mon, 22 Oct 2018 08:04:03 -0700 Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxx> CommitDate: Thu, 8 Nov 2018 21:41:57 -0800 rcu: Eliminate BUG_ON() for kernel/rcu/tree.c 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@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx> --- kernel/rcu/tree.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 121f833acd04..bdb6659a8dbc 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -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;
|