| Message ID | 20190212025632.28946-16-peterx@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | userfaultfd: write protection support | expand |
On Tue, Feb 12, 2019 at 10:56:21AM +0800, Peter Xu wrote: > UFFD_EVENT_FORK support for uffd-wp should be already there, except > that we should clean the uffd-wp bit if uffd fork event is not > enabled. Detect that to avoid _PAGE_UFFD_WP being set even if the VMA > is not being tracked by VM_UFFD_WP. Do this for both small PTEs and > huge PMDs. > > Signed-off-by: Peter Xu <peterx@redhat.com> This patch must be earlier in the serie, before the patch that introduce the userfaultfd API so that bisect can not end up on version where this can happen. Otherwise the patch itself is: Reviewed-by: Jérôme Glisse <jglisse@redhat.com> > --- > mm/huge_memory.c | 8 ++++++++ > mm/memory.c | 8 ++++++++ > 2 files changed, 16 insertions(+) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 817335b443c2..fb2234cb595a 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -938,6 +938,14 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, > ret = -EAGAIN; > pmd = *src_pmd; > > + /* > + * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA > + * does not have the VM_UFFD_WP, which means that the uffd > + * fork event is not enabled. > + */ > + if (!(vma->vm_flags & VM_UFFD_WP)) > + pmd = pmd_clear_uffd_wp(pmd); > + > #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION > if (unlikely(is_swap_pmd(pmd))) { > swp_entry_t entry = pmd_to_swp_entry(pmd); > diff --git a/mm/memory.c b/mm/memory.c > index b5d67bafae35..c2035539e9fd 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -788,6 +788,14 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, > pte = pte_mkclean(pte); > pte = pte_mkold(pte); > > + /* > + * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA > + * does not have the VM_UFFD_WP, which means that the uffd > + * fork event is not enabled. > + */ > + if (!(vm_flags & VM_UFFD_WP)) > + pte = pte_clear_uffd_wp(pte); > + > page = vm_normal_page(vma, addr, pte); > if (page) { > get_page(page); > -- > 2.17.1 >
On Thu, Feb 21, 2019 at 01:06:31PM -0500, Jerome Glisse wrote: > On Tue, Feb 12, 2019 at 10:56:21AM +0800, Peter Xu wrote: > > UFFD_EVENT_FORK support for uffd-wp should be already there, except > > that we should clean the uffd-wp bit if uffd fork event is not > > enabled. Detect that to avoid _PAGE_UFFD_WP being set even if the VMA > > is not being tracked by VM_UFFD_WP. Do this for both small PTEs and > > huge PMDs. > > > > Signed-off-by: Peter Xu <peterx@redhat.com> > > This patch must be earlier in the serie, before the patch that introduce > the userfaultfd API so that bisect can not end up on version where this > can happen. Yes it should be now? Since the API will be introduced until patch 21/26 ("userfaultfd: wp: add the writeprotect API to userfaultfd ioctl"). > > Otherwise the patch itself is: > > Reviewed-by: Jérôme Glisse <jglisse@redhat.com> Unless I found anything I've missed above... I'll temporarily pick this R-b for now then. Thanks,
On Fri, Feb 22, 2019 at 05:09:19PM +0800, Peter Xu wrote: > On Thu, Feb 21, 2019 at 01:06:31PM -0500, Jerome Glisse wrote: > > On Tue, Feb 12, 2019 at 10:56:21AM +0800, Peter Xu wrote: > > > UFFD_EVENT_FORK support for uffd-wp should be already there, except > > > that we should clean the uffd-wp bit if uffd fork event is not > > > enabled. Detect that to avoid _PAGE_UFFD_WP being set even if the VMA > > > is not being tracked by VM_UFFD_WP. Do this for both small PTEs and > > > huge PMDs. > > > > > > Signed-off-by: Peter Xu <peterx@redhat.com> > > > > This patch must be earlier in the serie, before the patch that introduce > > the userfaultfd API so that bisect can not end up on version where this > > can happen. > > Yes it should be now? Since the API will be introduced until patch > 21/26 ("userfaultfd: wp: add the writeprotect API to userfaultfd > ioctl"). No i was confuse when reading this patch i had the feeling it was after the ioctl ignore my comment. > > > > > Otherwise the patch itself is: > > > > Reviewed-by: Jérôme Glisse <jglisse@redhat.com> > > Unless I found anything I've missed above... I'll temporarily pick > this R-b for now then. It is fine, the patch ordering was my confusion. Cheers, Jérôme
On Tue, Feb 12, 2019 at 10:56:21AM +0800, Peter Xu wrote: > UFFD_EVENT_FORK support for uffd-wp should be already there, except > that we should clean the uffd-wp bit if uffd fork event is not > enabled. Detect that to avoid _PAGE_UFFD_WP being set even if the VMA > is not being tracked by VM_UFFD_WP. Do this for both small PTEs and > huge PMDs. > > Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> > --- > mm/huge_memory.c | 8 ++++++++ > mm/memory.c | 8 ++++++++ > 2 files changed, 16 insertions(+) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 817335b443c2..fb2234cb595a 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -938,6 +938,14 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, > ret = -EAGAIN; > pmd = *src_pmd; > > + /* > + * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA > + * does not have the VM_UFFD_WP, which means that the uffd > + * fork event is not enabled. > + */ > + if (!(vma->vm_flags & VM_UFFD_WP)) > + pmd = pmd_clear_uffd_wp(pmd); > + > #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION > if (unlikely(is_swap_pmd(pmd))) { > swp_entry_t entry = pmd_to_swp_entry(pmd); > diff --git a/mm/memory.c b/mm/memory.c > index b5d67bafae35..c2035539e9fd 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -788,6 +788,14 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, > pte = pte_mkclean(pte); > pte = pte_mkold(pte); > > + /* > + * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA > + * does not have the VM_UFFD_WP, which means that the uffd > + * fork event is not enabled. > + */ > + if (!(vm_flags & VM_UFFD_WP)) > + pte = pte_clear_uffd_wp(pte); > + > page = vm_normal_page(vma, addr, pte); > if (page) { > get_page(page); > -- > 2.17.1 >
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 817335b443c2..fb2234cb595a 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -938,6 +938,14 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, ret = -EAGAIN; pmd = *src_pmd; + /* + * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA + * does not have the VM_UFFD_WP, which means that the uffd + * fork event is not enabled. + */ + if (!(vma->vm_flags & VM_UFFD_WP)) + pmd = pmd_clear_uffd_wp(pmd); + #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION if (unlikely(is_swap_pmd(pmd))) { swp_entry_t entry = pmd_to_swp_entry(pmd); diff --git a/mm/memory.c b/mm/memory.c index b5d67bafae35..c2035539e9fd 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -788,6 +788,14 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, pte = pte_mkclean(pte); pte = pte_mkold(pte); + /* + * Make sure the _PAGE_UFFD_WP bit is cleared if the new VMA + * does not have the VM_UFFD_WP, which means that the uffd + * fork event is not enabled. + */ + if (!(vm_flags & VM_UFFD_WP)) + pte = pte_clear_uffd_wp(pte); + page = vm_normal_page(vma, addr, pte); if (page) { get_page(page);
UFFD_EVENT_FORK support for uffd-wp should be already there, except that we should clean the uffd-wp bit if uffd fork event is not enabled. Detect that to avoid _PAGE_UFFD_WP being set even if the VMA is not being tracked by VM_UFFD_WP. Do this for both small PTEs and huge PMDs. Signed-off-by: Peter Xu <peterx@redhat.com> --- mm/huge_memory.c | 8 ++++++++ mm/memory.c | 8 ++++++++ 2 files changed, 16 insertions(+)