From: Steven Rostedt <rostedt@goodmis.org>
Date: Thu, 15 Nov 2012 17:52:44 +0000 (-0500)
Subject: irq_work: Warn if there's still work on cpu_down
X-Git-Tag: firefly_0821_release~3680^2~1127^2~1^2~2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8aa2accee41f7045dc904fa41d4475b2f6ffae3e;p=firefly-linux-kernel-4.4.55.git

irq_work: Warn if there's still work on cpu_down

If we are in nohz and there's still irq_work to be done when the idle
task is about to go offline, give a nasty warning. Everything should
have been flushed from the CPU_DYING notifier already. Further attempts
to enqueue an irq_work are buggy because irqs are disabled by
__cpu_disable(). The best we can do is to report the issue to the user.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 4ed17490f629..480f74715ba9 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -109,6 +109,9 @@ bool irq_work_needs_cpu(void)
 	if (llist_empty(this_list))
 		return false;
 
+	/* All work should have been flushed before going offline */
+	WARN_ON_ONCE(cpu_is_offline(smp_processor_id()));
+
 	return true;
 }