Messages in this thread Patch in this message | | | Date | Sun, 13 Apr 2014 09:48:28 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH] sched/cpupri: fix cpupri_find() for high priority tasks |
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Actually, since task_pri is calculated from convert_prio() that check should never be hit. But, I'm paranoid, and instead of dropping the check, we can do the same as what cpupri_set() does. Which is to BUG.
-- Steve
From aac271901d6ef5ad19c52f166bf130ad27515b5f Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org> Date: Sun, 13 Apr 2014 09:34:53 -0400 Subject: [PATCH] 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.
Link: http://lkml.kernel.org/r/1397015410.5212.13.camel@marge.simpson.net
Cc: stable@vger.kernel.org Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- kernel/sched/cpupri.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c index 8b836b3..3031bac 100644 --- a/kernel/sched/cpupri.c +++ b/kernel/sched/cpupri.c @@ -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]; -- 1.8.1.4
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