From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri, 25 Jan 2008 20:08:34 +0000 (+0100)
Subject: sched: fix: don't take a mutex from interrupt context
X-Git-Tag: v2.6.25-rc1~1237^2~2
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5973e5b954848c63855a357ad4ff39882e3904f7;p=linux-2.6

sched: fix: don't take a mutex from interrupt context

print_cfs_stats is callable from interrupt context (sysrq), hence it should
not take mutexes. Change it to use RCU since the task group data is RCU
freed anyway.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 1b3b40ad7c..45ff4e9411 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1434,9 +1434,9 @@ static void print_cfs_stats(struct seq_file *m, int cpu)
 #ifdef CONFIG_FAIR_GROUP_SCHED
 	print_cfs_rq(m, cpu, &cpu_rq(cpu)->cfs);
 #endif
-	lock_task_group_list();
+	rcu_read_lock();
 	for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq)
 		print_cfs_rq(m, cpu, cfs_rq);
-	unlock_task_group_list();
+	rcu_read_unlock();
 }
 #endif