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Commit d95ca82a authored by Vinayak Menon's avatar Vinayak Menon
Browse files

mm: skip speculative path for non-anonymous COW faults 



anon_vma_prepare should not called in speculative page fault
path. But a non-anonymous private COW page without anon_vma
can enter it on a write. Fix it.

Change-Id: I107b793392ba436fbe0f07f93f67767eaf1446e6
Signed-off-by: default avatarVinayak Menon <vinmenon@codeaurora.org>
parent 1a5ca59c

mm/memory.c

+5 −1
Original line number Diff line number Diff line
@@ -4260,7 +4260,11 @@ int __handle_speculative_fault(struct mm_struct *mm, unsigned long address, 
	 * because vm_next and vm_prev must be safe. This can't be guaranteed

	 * in the speculative path.

	 */

	if (unlikely(vma_is_anonymous(vmf.vma) && !vmf.vma->anon_vma))

	if (unlikely((vma_is_anonymous(vmf.vma) && !vmf.vma->anon_vma) ||

		(!vma_is_anonymous(vmf.vma) &&

			!(vmf.vma->vm_flags & VM_SHARED) &&

			(vmf.flags & FAULT_FLAG_WRITE) &&

			!vmf.vma->anon_vma)))

		return VM_FAULT_RETRY;



	vmf.vma_flags = READ_ONCE(vmf.vma->vm_flags);