Re: [PATCH v23 12/28] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY to _PAGE_COW
From: Kirill A. Shutemov <hidden>
Date: 2021-03-22 11:39:43
Also in:
linux-arch, linux-doc, linux-mm, lkml
On Mon, Mar 22, 2021 at 11:46:21AM +0100, Peter Zijlstra wrote:
On Mon, Mar 22, 2021 at 01:15:02PM +0300, Kirill A. Shutemov wrote:quoted
On Tue, Mar 16, 2021 at 08:10:38AM -0700, Yu-cheng Yu wrote:quoted
quoted
+ pte_t old_pte, new_pte; + + old_pte = READ_ONCE(*ptep); + do { + new_pte = pte_wrprotect(old_pte); + } while (!try_cmpxchg(&ptep->pte, &old_pte.pte, new_pte.pte));I think this is wrong. You need to update old_pte on every loop iteration, otherwise you can get in to endless loop.It is correct, please consider why the old argument is a pointer.
Ah, right. Sorry for the noise. -- Kirill A. Shutemov