powerpc: fix memory corruption by pnv_alloc_idle_core_states

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>

diff --git a/arch/powerpc/include/asm/cputhreads.h b/arch/powerpc/include/asm/cputhreads.h
index 2bf8e9307be9833b5bf9af51defdfada8feae68d..4c8ad592ae3351d96f7e225411d9f551657c5bc7 100644 (file)
--- 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_to_cores(const struct cpumask *threads)
 
 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)