From 8e85b4b553fc932e1c5141feb5fda389b7f5db01 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 2 Oct 2008 10:50:53 +0200
Subject: [PATCH] softirqs, debug: preemption check
if a preempt count leaks out of a softirq handler it can be very hard
to figure it out. Add a debug check for this.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/softirq.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 82e32aadedd..1cf1e2f2c40 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -205,7 +205,18 @@ restart:
do {
if (pending & 1) {
+ int prev_count = preempt_count();
+
h->action(h);
+
+ if (unlikely(prev_count != preempt_count())) {
+ printk(KERN_ERR "huh, entered sotfirq %ld %p"
+ "with preempt_count %08x,"
+ " exited with %08x?\n", h - softirq_vec,
+ h->action, prev_count, preempt_count());
+ preempt_count() = prev_count;
+ }
+
rcu_bh_qsctr_inc(cpu);
}
h++;
--
2.41.3