| From | Ben Hutchings <> | Date | Sat, 07 Jun 2014 02:26:29 +0100 | Subject | [PATCH 3.2 61/92] sched: Use CPUPRI_NR_PRIORITIES instead of MAX_RT_PRIO in cpupri check |
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3.2.60-rc1 review patch. If anyone has any objections, please let me know.
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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
commit 6227cb00cc120f9a43ce8313bb0475ddabcb7d01 upstream.
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> Link: http://lkml.kernel.org/r/1397015410.5212.13.camel@marge.simpson.net Signed-off-by: Ingo Molnar <mingo@kernel.org> [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- kernel/sched/cpupri.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/kernel/sched_cpupri.c +++ b/kernel/sched_cpupri.c @@ -68,8 +68,7 @@ int cpupri_find(struct cpupri *cp, struc 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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