powerpc/mm: Handle hypervisor pte insert failure in __hash_page_huge

If the hypervisor gives us an error on a hugepage insert we panic. The
normal page code already handles this by returning an error instead and we end
calling low_hash_fault which will just kill the task if possible.

The patch below does a similar thing for the hugepage case.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 9 insertions, 2 deletions

diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c
index 199539882f92..c9acd7910eea 100644
--- a/arch/powerpc/mm/hugetlbpage-hash64.c
+++ b/arch/powerpc/mm/hugetlbpage-hash64.c
@@ -121,8 +121,15 @@ repeat:
                         }
                 }
 
-                if (unlikely(slot == -2))
-                        panic("hash_huge_page: pte_insert failed\n");
+                /*
+                 * Hypervisor failure. Restore old pte and return -1
+                 * similar to __hash_page_*
+                 */
+                if (unlikely(slot == -2)) {
+                        *ptep = __pte(old_pte);
+                        err = -1;
+                        goto out;
+                }
 
                 new_pte |= (slot << 12) & (_PAGE_F_SECOND | _PAGE_F_GIX);
         }