Commit 6227cb00 authored Apr 13, 2014 by Steven Rostedt (Red Hat) Committed by Ingo Molnar May 07, 2014

sched: Use CPUPRI_NR_PRIORITIES instead of MAX_RT_PRIO in cpupri check



The check at the beginning of cpupri_find() makes sure that the task_pri
variable does not exceed the cp->pri_to_cpu array length. But that length
is CPUPRI_NR_PRIORITIES not MAX_RT_PRIO, where it will miss the last two
priorities in that array.

As task_pri is computed from convert_prio() which should never be bigger
than CPUPRI_NR_PRIORITIES, if the check should cause a panic if it is
hit.

Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1397015410.5212.13.camel@marge.simpson.net


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 6a7cd273

kernel/sched/cpupri.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -70,8 +70,7 @@ int cpupri_find(struct cpupri cp, struct task_struct p,
		int idx = 0;
		int task_pri = convert_prio(p->prio);

		if (task_pri >= MAX_RT_PRIO)
		return 0;
		BUG_ON(task_pri >= CPUPRI_NR_PRIORITIES);

		for (idx = 0; idx < task_pri; idx++) {
		struct cpupri_vec *vec = &cp->pri_to_cpu[idx];

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