> On Aug 22, 2022, at 16:45, Miaohe Lin <linmiaohe@xxxxxxxxxx> wrote: > > On 2022/8/20 16:12, Muchun Song wrote: >> >> >>> On Aug 16, 2022, at 21:05, Miaohe Lin <linmiaohe@xxxxxxxxxx> wrote: >>> >>> The memory barrier smp_wmb() is needed to make sure that preceding stores >>> to the page contents become visible before the below set_pte_at() write. >> >> I found another place where is a similar case. See kasan_populate_vmalloc_pte() in >> mm/kasan/shadow.c. > > Thanks for your report. > >> >> Should we fix it as well? > > I'm not familiar with kasan yet, but I think memory barrier is needed here or memory corrupt > can't be detected until the contents are visible. smp_mb__after_atomic before set_pte_at should > be enough? What's your opinion? I didn’t see any atomic operation between set_pte_at() and memset(), I don’t think smp_mb__after_atomic() is feasible if we really need to insert a barrier. I suggest you to send a RFC patch to KASAN maintainers, they are more familiar with this than us. Thanks. > > Thanks, > Miaohe Lin > >
