Commit-ID: 0da938c44921cfb690283d3b0c9c48a10375db2c Gitweb: http://git.kernel.org/tip/0da938c44921cfb690283d3b0c9c48a10375db2c Author: Steven Rostedt <rostedt@xxxxxxxxxxx> AuthorDate: Tue, 14 Jun 2011 18:36:25 -0400 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Wed, 15 Jun 2011 11:44:48 +0200 sched: Check if lowest_mask is initialized in find_lowest_rq() On system boot up, the lowest_mask is initialized with an early_initcall(). But RT tasks may wake up on other early_initcall() callers before the lowest_mask is initialized, causing a system crash. Commit "d72bce0e67 rcu: Cure load woes" was the first commit to wake up RT tasks in early init. Before this commit this bug should not happen. Reported-by: Andrew Theurer <habanero@xxxxxxxxxxxxxxxxxx> Tested-by: Andrew Theurer <habanero@xxxxxxxxxxxxxxxxxx> Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/20110614223657.824872966@xxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- kernel/sched_rt.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 9b8d5dc..10d0182 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -1239,6 +1239,10 @@ static int find_lowest_rq(struct task_struct *task) int this_cpu = smp_processor_id(); int cpu = task_cpu(task); + /* Make sure the mask is initialized first */ + if (unlikely(!lowest_mask)) + return -1; + if (task->rt.nr_cpus_allowed == 1) return -1; /* No other targets possible */ -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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