Re: [PATCH v6 03/23] mm: Check against orig_pte for finish_fault()
From: Alistair Popple <apopple@nvidia.com>
Date: 2021-12-16 05:02:00
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On Monday, 15 November 2021 6:55:02 PM AEDT Peter Xu wrote:
We used to check against none pte and in those cases orig_pte should always be none pte anyway.
Is that always true? From what I can see in handle_pte_fault() orig_pte only gets initialised in the !pmd_none() case so might not be pte_none.
quoted hunk ↗ jump to hunk
This change prepares us to be able to call do_fault() on !none ptes. For example, we should allow that to happen for pte marker so that we can restore information out of the pte markers. Signed-off-by: Peter Xu <peterx@redhat.com> --- mm/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/mm/memory.c b/mm/memory.c index 04662b010005..d5966d9e24c3 100644 --- a/mm/memory.c +++ b/mm/memory.c@@ -4052,7 +4052,7 @@ vm_fault_t finish_fault(struct vm_fault *vmf) vmf->address, &vmf->ptl); ret = 0; /* Re-check under ptl */ - if (likely(pte_none(*vmf->pte))) + if (likely(pte_same(*vmf->pte, vmf->orig_pte))) do_set_pte(vmf, page, vmf->address); else ret = VM_FAULT_NOPAGE;