Re: [PATCH] mm: mmu_notifier: fix inconsistent memory between secondary MMU and host
From: Hugh Dickins <hughd@google.com>
Date: 2012-08-22 04:13:02
Also in:
kvm, lkml
On Wed, 22 Aug 2012, Xiao Guangrong wrote:
On 08/21/2012 11:06 PM, Andrea Arcangeli wrote:quoted
The KSM usage of it looks safe because it will only establish readonly ptes with it.Hmm, in KSM code, i found this code in replace_page: set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot)); It is possible to establish a writable pte, no?
No: we only do KSM in private vmas (!VM_SHARED), and because of the need to CopyOnWrite in those, vm_page_prot excludes write permission: write permission has to be added on COW fault. Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>