On Wed, Apr 17, 2019 at 12:04:33PM -0700, Darrick J. Wong wrote: > diff --git a/mm/memory.c b/mm/memory.c > index ab650c21bccd..dfd5eba278d6 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2149,6 +2149,9 @@ static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) > > vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; > > + if (vmf->vma->vm_file && IS_IMMUTABLE(file_inode(vmf->vma->vm_file))) > + return VM_FAULT_SIGBUS; > + > ret = vmf->vma->vm_ops->page_mkwrite(vmf); > /* Restore original flags so that caller is not surprised */ > vmf->flags = old_flags; Shouldn't this check be moved before the modification of vmf->flags? It looks like do_page_mkwrite() isn't supposed to be returning with vmf->flags modified, lest "the caller gets surprised". - Ted
