Messages in this thread | | | Date | Mon, 22 Mar 2021 11:46:21 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v23 12/28] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY to _PAGE_COW |
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On Mon, Mar 22, 2021 at 01:15:02PM +0300, Kirill A. Shutemov wrote: > On Tue, Mar 16, 2021 at 08:10:38AM -0700, Yu-cheng Yu wrote:
> > + 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.
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