From 4c0526fca375be30b5a296094129fe051be65124 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Fri, 6 Oct 2023 20:53:18 +0100 Subject: [PATCH] mm: handle write faults to RO pages under the VMA lock I think this is a pretty rare occurrence, but for consistency handle faults with the VMA lock held the same way that we handle other faults with the VMA lock held. Link: https://lkml.kernel.org/r/20231006195318.4087158-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton --- mm/memory.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index ff0dda9ef59fda..7f42d839076c95 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3304,10 +3304,9 @@ static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) vm_fault_t ret; pte_unmap_unlock(vmf->pte, vmf->ptl); - if (vmf->flags & FAULT_FLAG_VMA_LOCK) { - vma_end_read(vmf->vma); - return VM_FAULT_RETRY; - } + ret = vmf_can_call_fault(vmf); + if (ret) + return ret; vmf->flags |= FAULT_FLAG_MKWRITE; ret = vma->vm_ops->pfn_mkwrite(vmf); @@ -3331,10 +3330,10 @@ static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio) vm_fault_t tmp; pte_unmap_unlock(vmf->pte, vmf->ptl); - if (vmf->flags & FAULT_FLAG_VMA_LOCK) { + tmp = vmf_can_call_fault(vmf); + if (tmp) { folio_put(folio); - vma_end_read(vmf->vma); - return VM_FAULT_RETRY; + return tmp; } tmp = do_page_mkwrite(vmf, folio);