[POWERPC] Fix idr locking in init_new_context

We always need to serialize accesses to mmu_context_idr.

I hit this bug when testing with a small number of mmu contexts.

Signed-off-by: Sonny Rao <sonny@burdell.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/powerpc/mm/mmu_context_64.c b/arch/powerpc/mm/mmu_context_64.c
index 65d18dca266f..e2051efa09c5 100644
--- a/arch/powerpc/mm/mmu_context_64.c
+++ b/arch/powerpc/mm/mmu_context_64.c
@@ -44,7 +44,9 @@ again:
                 return err;
 
         if (index > MAX_CONTEXT) {
+                spin_lock(&mmu_context_lock);
                 idr_remove(&mmu_context_idr, index);
+                spin_unlock(&mmu_context_lock);
                 return -ENOMEM;
         }