Commit-ID: 9213784b48f8ba666b4695ca3f5d34f583daab83
Gitweb: https://git.kernel.org/tip/9213784b48f8ba666b4695ca3f5d34f583daab83
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
AuthorDate: Mon, 22 Oct 2018 08:26:00 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
CommitDate: Mon, 12 Nov 2018 08:15:16 -0800
rcu: Eliminate BUG_ON() for kernel/rcu/tree_plugin.h
The tree_plugin.h 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>
[ paulmck: Fix typo: s/rcuo/rcub/. ]
---
kernel/rcu/tree_plugin.h | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 05915e536336..adda608874a8 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1464,7 +1464,8 @@ static void __init rcu_spawn_boost_kthreads(void)
for_each_possible_cpu(cpu)
per_cpu(rcu_cpu_has_work, cpu) = 0;
- BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec));
+ if (WARN_ONCE(smpboot_register_percpu_thread(&rcu_cpu_thread_spec), "%s: Could not start rcub kthread, OOM is now expected behavior\n", __func__))
+ return;
rcu_for_each_leaf_node(rnp)
(void)rcu_spawn_one_boost_kthread(rnp);
}
@@ -2322,7 +2323,8 @@ static int rcu_nocb_kthread(void *arg)
tail = rdp->nocb_follower_tail;
rdp->nocb_follower_tail = &rdp->nocb_follower_head;
raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags);
- BUG_ON(!list);
+ if (WARN_ON_ONCE(!list))
+ continue;
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WokeNonEmpty"));
/* Each pass through the following loop invokes a callback. */
@@ -2495,7 +2497,8 @@ static void rcu_spawn_one_nocb_kthread(int cpu)
/* Spawn the kthread for this CPU. */
t = kthread_run(rcu_nocb_kthread, rdp_spawn,
"rcuo%c/%d", rcu_state.abbr, cpu);
- BUG_ON(IS_ERR(t));
+ if (WARN_ONCE(IS_ERR(t), "%s: Could not start rcuo kthread, OOM is now expected behavior\n", __func__))
+ return;
WRITE_ONCE(rdp_spawn->nocb_kthread, t);
}
|