[PATCH 1/8] sched: fix incorrect irq lock usage in normalize_rt_tasks()

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

[-- Attachment #1: sched-fix-normalize-rt-tasks.patch --]
[-- Type: text/plain, Size: 1114 bytes --]

lockdep spotted this bogus irq locking. normalize_rt_tasks() can be called
from hardirq context through sysrq-n

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 kernel/sched.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -7345,7 +7345,7 @@ void normalize_rt_tasks(void)
 	unsigned long flags;
 	struct rq *rq;
 
-	read_lock_irq(&tasklist_lock);
+	read_lock_irqsave(&tasklist_lock, flags);
 	do_each_thread(g, p) {
 		/*
 		 * Only normalize user tasks:
@@ -7371,16 +7371,16 @@ void normalize_rt_tasks(void)
 			continue;
 		}
 
-		spin_lock_irqsave(&p->pi_lock, flags);
+		spin_lock(&p->pi_lock);
 		rq = __task_rq_lock(p);
 
 		normalize_task(rq, p);
 
 		__task_rq_unlock(rq);
-		spin_unlock_irqrestore(&p->pi_lock, flags);
+		spin_unlock(&p->pi_lock);
 	} while_each_thread(g, p);
 
-	read_unlock_irq(&tasklist_lock);
+	read_unlock_irqrestore(&tasklist_lock, flags);
 }
 
 #endif /* CONFIG_MAGIC_SYSRQ */

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