Commit c64be78f authored Jul 11, 2011 by Peter Zijlstra Committed by Linus Torvalds Jul 15, 2011

sched: Fix 32bit race



Commit 3fe1698b ("sched: Deal with non-atomic min_vruntime reads
on 32bit") forgot to initialize min_vruntime_copy which could lead to
an infinite while loop in task_waking_fair() under some circumstances
(early boot, lucky timing).

[ This bug was also reported by others that blamed it on the RCU
  initialization problems ]

Reported-and-tested-by: Bruno Wolff III <bruno@wolff.to>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 5dcd07b9

kernel/sched.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -7757,6 +7757,9 @@ static void init_cfs_rq(struct cfs_rq cfs_rq, struct rq rq)
		#endif
		#endif
		cfs_rq->min_vruntime = (u64)(-(1LL << 20));
		#ifndef CONFIG_64BIT
		cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
		#endif
		}

		static void init_rt_rq(struct rt_rq rt_rq, struct rq rq)

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