[PATCH 3.19 039/101] powerpc: fix memory corruption by pnv_alloc_idle_core_states

Greg Kroah-Hartman
2015-04-17T13:35:27Z

From: Jan Stancek <jstancek@redhat.com>

commit d52356e7f48e400ca258c6763a232a92fa82ff68 upstream.

Space allocated for paca is based off nr_cpu_ids,
but pnv_alloc_idle_core_states() iterates paca with
cpu_nr_cores()*threads_per_core, which is using NR_CPUS.

This causes pnv_alloc_idle_core_states() to write over memory,
which is outside of paca array and may later lead to various panics.

Fixes: 7cba160ad789 (powernv/cpuidle: Redesign idle states management)
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Preet U. Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/include/asm/cputhreads.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/include/asm/cputhreads.h
+++ b/arch/powerpc/include/asm/cputhreads.h
@@ -55,7 +55,7 @@ static inline cpumask_t cpu_thread_mask_

static inline int cpu_nr_cores(void)
{
- return NR_CPUS >> threads_shift;
+ return nr_cpu_ids >> threads_shift;
}

static inline cpumask_t cpu_online_cores_map(void)