Commit c64be78f authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Linus Torvalds

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: default avatarBruno Wolff III <bruno@wolff.to>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5dcd07b9
...@@ -7757,6 +7757,9 @@ static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) ...@@ -7757,6 +7757,9 @@ static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
#endif #endif
#endif #endif
cfs_rq->min_vruntime = (u64)(-(1LL << 20)); 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) static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
......
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