Commit 00214085 authored Nov 29, 2023 by Matthew Wilcox (Oracle) Committed by Tong Tiangen Nov 29, 2023

mm: handle write faults to RO pages under the VMA lock

mainline inclusion
from mainline-v6.7-rc1
commit 4a68fef16df9d88d528094116f8bbd2dbfa62089
category: other
bugzilla: https://gitee.com/openeuler/kernel/issues/I8K7C7

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4a68fef16df9d88d528094116f8bbd2dbfa62089

--------------------------------

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) <willy@infradead.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>

parent 83f90f21

mm/memory.c

+6 −7

Original line number	Diff line number	Diff line
		@@ -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);