1 files changed, 11 insertions, 1 deletions

diff --git a/mm/memory.c b/mm/memory.c
index e158f7ac6730..c717b5bcc80e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3910,8 +3910,18 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
          * further.
          */
         if (unlikely((current->flags & PF_KTHREAD) && !(ret & VM_FAULT_ERROR)
-                                && test_bit(MMF_UNSTABLE, &vma->vm_mm->flags)))
+                                && test_bit(MMF_UNSTABLE, &vma->vm_mm->flags))) {
+
+                /*
+                 * We are going to enforce SIGBUS but the PF path might have
+                 * dropped the mmap_sem already so take it again so that
+                 * we do not break expectations of all arch specific PF paths
+                 * and g-u-p
+                 */
+                if (ret & VM_FAULT_RETRY)
+                        down_read(&vma->vm_mm->mmap_sem);
                 ret = VM_FAULT_SIGBUS;
+        }
 
         return ret;
 }