add proposed fix for LP#1674838
Patches and rationale by Seth Forshee[1]: My testing shows that the "POWER9: Additional power9 patches" patches are responsible, two of them in particular: - mm: introduce page_vma_mapped_walk() - mm, ksm: convert write_protect_page() to use page_vma_mapped_walk() These patches don't appear to be included for any functionality they provide, but rather to make "mm/ksm: handle protnone saved writes when making page write protect" a clean cherry pick instead of a backport. But the backport isn't that difficult, so as far as I can tell we can do away with the other two patches. 1: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1674838/comments/108
This commit is contained in:
Fabian Grünbichler
parent
7f0f6370be
commit
2b834b083d
5 changed files with 543 additions and 0 deletions
4
Makefile
4
Makefile
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@ -229,6 +229,10 @@ ${KERNEL_SRC}/README ${KERNEL_CFG_ORG}: ${KERNEL_SRC_SUBMODULE} | submodules
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cd ${KERNEL_SRC}; patch -p1 < ../openvswitch-Set-internal-device-max-mtu-to-ETH_MAX_M.patch
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cd ${KERNEL_SRC}; patch -p1 < ../CVE-2017-7979-0001-net_sched-nla_memdup_cookie-can-be-static.patch
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cd ${KERNEL_SRC}; patch -p1 < ../CVE-2017-7979-0002-net-sched-actions-allocate-act-cookie-early.patch
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cd ${KERNEL_SRC}; patch -p1 < ../swapops-0001-Revert-mm-ksm-handle-protnone-saved-writes-when-maki.patch
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cd ${KERNEL_SRC}; patch -p1 < ../swapops-0002-Revert-mm-ksm-convert-write_protect_page-to-use-page.patch
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cd ${KERNEL_SRC}; patch -p1 < ../swapops-0003-Revert-mm-introduce-page_vma_mapped_walk.patch
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cd ${KERNEL_SRC}; patch -p1 < ../swapops-0004-mm-ksm-handle-protnone-saved-writes-when-making-page.patch
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sed -i ${KERNEL_SRC}/Makefile -e 's/^EXTRAVERSION.*$$/EXTRAVERSION=${EXTRAVERSION}/'
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touch $@
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@ -0,0 +1,70 @@
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From b4cf3c107f8f1d2da2b606e9d08e241be7000d65 Mon Sep 17 00:00:00 2001
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From: Seth Forshee <seth.forshee@canonical.com>
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Date: Wed, 3 May 2017 08:34:47 -0500
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Subject: [PATCH 1/4] Revert "mm/ksm: handle protnone saved writes when making
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page write protect"
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This reverts commit c228a1037cd6bd0064472ea282e3730a342d6fca.
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Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
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---
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include/asm-generic/pgtable.h | 8 --------
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mm/ksm.c | 9 ++-------
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2 files changed, 2 insertions(+), 15 deletions(-)
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diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
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index 8c8ba48bef0b..b6f3a8a4b738 100644
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--- a/include/asm-generic/pgtable.h
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+++ b/include/asm-generic/pgtable.h
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@@ -200,10 +200,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
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#define pte_mk_savedwrite pte_mkwrite
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#endif
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-#ifndef pte_clear_savedwrite
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-#define pte_clear_savedwrite pte_wrprotect
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-#endif
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-
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#ifndef pmd_savedwrite
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#define pmd_savedwrite pmd_write
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#endif
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@@ -212,10 +208,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
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#define pmd_mk_savedwrite pmd_mkwrite
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#endif
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-#ifndef pmd_clear_savedwrite
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-#define pmd_clear_savedwrite pmd_wrprotect
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-#endif
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-
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#ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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static inline void pmdp_set_wrprotect(struct mm_struct *mm,
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diff --git a/mm/ksm.c b/mm/ksm.c
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index abc05187168a..9dd2e58fb6dc 100644
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--- a/mm/ksm.c
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+++ b/mm/ksm.c
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@@ -880,8 +880,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
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if (WARN_ONCE(!pvmw.pte, "Unexpected PMD mapping?"))
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goto out_unlock;
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- if (pte_write(*pvmw.pte) || pte_dirty(*pvmw.pte) ||
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- (pte_protnone(*pvmw.pte) && pte_savedwrite(*pvmw.pte))) {
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+ if (pte_write(*pvmw.pte) || pte_dirty(*pvmw.pte)) {
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pte_t entry;
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swapped = PageSwapCache(page);
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@@ -906,11 +905,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
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}
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if (pte_dirty(entry))
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set_page_dirty(page);
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-
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- if (pte_protnone(entry))
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- entry = pte_mkclean(pte_clear_savedwrite(entry));
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- else
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- entry = pte_mkclean(pte_wrprotect(entry));
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+ entry = pte_mkclean(pte_wrprotect(entry));
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set_pte_at_notify(mm, pvmw.address, pvmw.pte, entry);
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}
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*orig_pte = *pvmw.pte;
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--
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2.7.4
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@ -0,0 +1,98 @@
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From 40e1fa51bc8aa3df1d3a23711b5de62d8251bff5 Mon Sep 17 00:00:00 2001
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From: Seth Forshee <seth.forshee@canonical.com>
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Date: Wed, 3 May 2017 08:34:52 -0500
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Subject: [PATCH 2/4] Revert "mm, ksm: convert write_protect_page() to use
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page_vma_mapped_walk()"
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This reverts commit 3000e033152a70fa139765b4dbb5baec46b1cc1b.
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Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
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---
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mm/ksm.c | 34 ++++++++++++++++------------------
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1 file changed, 16 insertions(+), 18 deletions(-)
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diff --git a/mm/ksm.c b/mm/ksm.c
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index 9dd2e58fb6dc..fed4afd8293b 100644
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--- a/mm/ksm.c
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+++ b/mm/ksm.c
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@@ -856,35 +856,33 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
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pte_t *orig_pte)
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{
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struct mm_struct *mm = vma->vm_mm;
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- struct page_vma_mapped_walk pvmw = {
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- .page = page,
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- .vma = vma,
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- };
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+ unsigned long addr;
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+ pte_t *ptep;
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+ spinlock_t *ptl;
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int swapped;
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int err = -EFAULT;
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unsigned long mmun_start; /* For mmu_notifiers */
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unsigned long mmun_end; /* For mmu_notifiers */
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- pvmw.address = page_address_in_vma(page, vma);
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- if (pvmw.address == -EFAULT)
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+ addr = page_address_in_vma(page, vma);
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+ if (addr == -EFAULT)
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goto out;
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BUG_ON(PageTransCompound(page));
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- mmun_start = pvmw.address;
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- mmun_end = pvmw.address + PAGE_SIZE;
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+ mmun_start = addr;
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+ mmun_end = addr + PAGE_SIZE;
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mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
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- if (!page_vma_mapped_walk(&pvmw))
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+ ptep = page_check_address(page, mm, addr, &ptl, 0);
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+ if (!ptep)
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goto out_mn;
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- if (WARN_ONCE(!pvmw.pte, "Unexpected PMD mapping?"))
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- goto out_unlock;
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- if (pte_write(*pvmw.pte) || pte_dirty(*pvmw.pte)) {
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+ if (pte_write(*ptep) || pte_dirty(*ptep)) {
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pte_t entry;
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swapped = PageSwapCache(page);
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- flush_cache_page(vma, pvmw.address, page_to_pfn(page));
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+ flush_cache_page(vma, addr, page_to_pfn(page));
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/*
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* Ok this is tricky, when get_user_pages_fast() run it doesn't
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* take any lock, therefore the check that we are going to make
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@@ -894,25 +892,25 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
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* this assure us that no O_DIRECT can happen after the check
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* or in the middle of the check.
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*/
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- entry = ptep_clear_flush_notify(vma, pvmw.address, pvmw.pte);
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+ entry = ptep_clear_flush_notify(vma, addr, ptep);
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/*
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* Check that no O_DIRECT or similar I/O is in progress on the
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* page
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*/
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if (page_mapcount(page) + 1 + swapped != page_count(page)) {
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- set_pte_at(mm, pvmw.address, pvmw.pte, entry);
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+ set_pte_at(mm, addr, ptep, entry);
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goto out_unlock;
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}
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if (pte_dirty(entry))
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set_page_dirty(page);
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entry = pte_mkclean(pte_wrprotect(entry));
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- set_pte_at_notify(mm, pvmw.address, pvmw.pte, entry);
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+ set_pte_at_notify(mm, addr, ptep, entry);
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}
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- *orig_pte = *pvmw.pte;
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+ *orig_pte = *ptep;
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err = 0;
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out_unlock:
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- page_vma_mapped_walk_done(&pvmw);
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+ pte_unmap_unlock(ptep, ptl);
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out_mn:
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mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
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out:
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--
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2.7.4
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294
swapops-0003-Revert-mm-introduce-page_vma_mapped_walk.patch
Normal file
294
swapops-0003-Revert-mm-introduce-page_vma_mapped_walk.patch
Normal file
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@ -0,0 +1,294 @@
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From 47a3e75a6d3db759a5fce3e922f144af0d6f1d38 Mon Sep 17 00:00:00 2001
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From: Seth Forshee <seth.forshee@canonical.com>
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Date: Wed, 3 May 2017 08:34:56 -0500
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Subject: [PATCH 3/4] Revert "mm: introduce page_vma_mapped_walk()"
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This reverts commit 6e2a092a48d38cfc0f06bdb523014acbfeba7b2e.
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Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
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---
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include/linux/rmap.h | 26 -------
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mm/Makefile | 6 +-
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mm/huge_memory.c | 9 +--
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mm/page_vma_mapped.c | 188 ---------------------------------------------------
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4 files changed, 5 insertions(+), 224 deletions(-)
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delete mode 100644 mm/page_vma_mapped.c
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diff --git a/include/linux/rmap.h b/include/linux/rmap.h
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index b76343610653..15321fb1df6b 100644
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--- a/include/linux/rmap.h
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+++ b/include/linux/rmap.h
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@@ -9,7 +9,6 @@
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#include <linux/mm.h>
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#include <linux/rwsem.h>
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#include <linux/memcontrol.h>
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-#include <linux/highmem.h>
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/*
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* The anon_vma heads a list of private "related" vmas, to scan if
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@@ -233,31 +232,6 @@ static inline bool page_check_address_transhuge(struct page *page,
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}
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#endif
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-/* Avoid racy checks */
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-#define PVMW_SYNC (1 << 0)
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-/* Look for migarion entries rather than present PTEs */
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-#define PVMW_MIGRATION (1 << 1)
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-
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-struct page_vma_mapped_walk {
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- struct page *page;
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- struct vm_area_struct *vma;
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- unsigned long address;
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- pmd_t *pmd;
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- pte_t *pte;
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- spinlock_t *ptl;
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- unsigned int flags;
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-};
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-
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-static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
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-{
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- if (pvmw->pte)
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- pte_unmap(pvmw->pte);
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- if (pvmw->ptl)
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- spin_unlock(pvmw->ptl);
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-}
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-
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-bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw);
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-
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/*
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* Used by swapoff to help locate where page is expected in vma.
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*/
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diff --git a/mm/Makefile b/mm/Makefile
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index 474fa3431059..14fa1c83b504 100644
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--- a/mm/Makefile
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+++ b/mm/Makefile
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@@ -23,10 +23,8 @@ KCOV_INSTRUMENT_vmstat.o := n
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mmu-y := nommu.o
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mmu-$(CONFIG_MMU) := gup.o highmem.o memory.o mincore.o \
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- mlock.o mmap.o mprotect.o mremap.o msync.o \
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- page_vma_mapped.o pagewalk.o pgtable-generic.o \
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- rmap.o vmalloc.o
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-
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+ mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \
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+ vmalloc.o pagewalk.o pgtable-generic.o
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ifdef CONFIG_CROSS_MEMORY_ATTACH
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mmu-$(CONFIG_MMU) += process_vm_access.o
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diff --git a/mm/huge_memory.c b/mm/huge_memory.c
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index 87303c6bacf4..e6de801fa477 100644
|
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--- a/mm/huge_memory.c
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+++ b/mm/huge_memory.c
|
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@@ -1878,12 +1878,9 @@ static void freeze_page(struct page *page)
|
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static void unfreeze_page(struct page *page)
|
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{
|
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int i;
|
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- if (PageTransHuge(page)) {
|
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- remove_migration_ptes(page, page, true);
|
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- } else {
|
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- for (i = 0; i < HPAGE_PMD_NR; i++)
|
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- remove_migration_ptes(page + i, page + i, true);
|
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- }
|
||||
+
|
||||
+ for (i = 0; i < HPAGE_PMD_NR; i++)
|
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+ remove_migration_ptes(page + i, page + i, true);
|
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}
|
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|
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static void __split_huge_page_tail(struct page *head, int tail,
|
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diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
|
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deleted file mode 100644
|
||||
index dc1a54826cf2..000000000000
|
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--- a/mm/page_vma_mapped.c
|
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+++ /dev/null
|
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@@ -1,188 +0,0 @@
|
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-#include <linux/mm.h>
|
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-#include <linux/rmap.h>
|
||||
-#include <linux/hugetlb.h>
|
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-#include <linux/swap.h>
|
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-#include <linux/swapops.h>
|
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-
|
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-#include "internal.h"
|
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-
|
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-static inline bool check_pmd(struct page_vma_mapped_walk *pvmw)
|
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-{
|
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- pmd_t pmde;
|
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- /*
|
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- * Make sure we don't re-load pmd between present and !trans_huge check.
|
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- * We need a consistent view.
|
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- */
|
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- pmde = READ_ONCE(*pvmw->pmd);
|
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- return pmd_present(pmde) && !pmd_trans_huge(pmde);
|
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-}
|
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-
|
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-static inline bool not_found(struct page_vma_mapped_walk *pvmw)
|
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-{
|
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- page_vma_mapped_walk_done(pvmw);
|
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- return false;
|
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-}
|
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-
|
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-static bool map_pte(struct page_vma_mapped_walk *pvmw)
|
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-{
|
||||
- pvmw->pte = pte_offset_map(pvmw->pmd, pvmw->address);
|
||||
- if (!(pvmw->flags & PVMW_SYNC)) {
|
||||
- if (pvmw->flags & PVMW_MIGRATION) {
|
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- if (!is_swap_pte(*pvmw->pte))
|
||||
- return false;
|
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- } else {
|
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- if (!pte_present(*pvmw->pte))
|
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- return false;
|
||||
- }
|
||||
- }
|
||||
- pvmw->ptl = pte_lockptr(pvmw->vma->vm_mm, pvmw->pmd);
|
||||
- spin_lock(pvmw->ptl);
|
||||
- return true;
|
||||
-}
|
||||
-
|
||||
-static bool check_pte(struct page_vma_mapped_walk *pvmw)
|
||||
-{
|
||||
- if (pvmw->flags & PVMW_MIGRATION) {
|
||||
-#ifdef CONFIG_MIGRATION
|
||||
- swp_entry_t entry;
|
||||
- if (!is_swap_pte(*pvmw->pte))
|
||||
- return false;
|
||||
- entry = pte_to_swp_entry(*pvmw->pte);
|
||||
- if (!is_migration_entry(entry))
|
||||
- return false;
|
||||
- if (migration_entry_to_page(entry) - pvmw->page >=
|
||||
- hpage_nr_pages(pvmw->page)) {
|
||||
- return false;
|
||||
- }
|
||||
- if (migration_entry_to_page(entry) < pvmw->page)
|
||||
- return false;
|
||||
-#else
|
||||
- WARN_ON_ONCE(1);
|
||||
-#endif
|
||||
- } else {
|
||||
- if (!pte_present(*pvmw->pte))
|
||||
- return false;
|
||||
-
|
||||
- /* THP can be referenced by any subpage */
|
||||
- if (pte_page(*pvmw->pte) - pvmw->page >=
|
||||
- hpage_nr_pages(pvmw->page)) {
|
||||
- return false;
|
||||
- }
|
||||
- if (pte_page(*pvmw->pte) < pvmw->page)
|
||||
- return false;
|
||||
- }
|
||||
-
|
||||
- return true;
|
||||
-}
|
||||
-
|
||||
-/**
|
||||
- * page_vma_mapped_walk - check if @pvmw->page is mapped in @pvmw->vma at
|
||||
- * @pvmw->address
|
||||
- * @pvmw: pointer to struct page_vma_mapped_walk. page, vma, address and flags
|
||||
- * must be set. pmd, pte and ptl must be NULL.
|
||||
- *
|
||||
- * Returns true if the page is mapped in the vma. @pvmw->pmd and @pvmw->pte point
|
||||
- * to relevant page table entries. @pvmw->ptl is locked. @pvmw->address is
|
||||
- * adjusted if needed (for PTE-mapped THPs).
|
||||
- *
|
||||
- * If @pvmw->pmd is set but @pvmw->pte is not, you have found PMD-mapped page
|
||||
- * (usually THP). For PTE-mapped THP, you should run page_vma_mapped_walk() in
|
||||
- * a loop to find all PTEs that map the THP.
|
||||
- *
|
||||
- * For HugeTLB pages, @pvmw->pte is set to the relevant page table entry
|
||||
- * regardless of which page table level the page is mapped at. @pvmw->pmd is
|
||||
- * NULL.
|
||||
- *
|
||||
- * Retruns false if there are no more page table entries for the page in
|
||||
- * the vma. @pvmw->ptl is unlocked and @pvmw->pte is unmapped.
|
||||
- *
|
||||
- * If you need to stop the walk before page_vma_mapped_walk() returned false,
|
||||
- * use page_vma_mapped_walk_done(). It will do the housekeeping.
|
||||
- */
|
||||
-bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
|
||||
-{
|
||||
- struct mm_struct *mm = pvmw->vma->vm_mm;
|
||||
- struct page *page = pvmw->page;
|
||||
- pgd_t *pgd;
|
||||
- pud_t *pud;
|
||||
-
|
||||
- /* The only possible pmd mapping has been handled on last iteration */
|
||||
- if (pvmw->pmd && !pvmw->pte)
|
||||
- return not_found(pvmw);
|
||||
-
|
||||
- /* Only for THP, seek to next pte entry makes sense */
|
||||
- if (pvmw->pte) {
|
||||
- if (!PageTransHuge(pvmw->page) || PageHuge(pvmw->page))
|
||||
- return not_found(pvmw);
|
||||
- goto next_pte;
|
||||
- }
|
||||
-
|
||||
- if (unlikely(PageHuge(pvmw->page))) {
|
||||
- /* when pud is not present, pte will be NULL */
|
||||
- pvmw->pte = huge_pte_offset(mm, pvmw->address);
|
||||
- if (!pvmw->pte)
|
||||
- return false;
|
||||
-
|
||||
- pvmw->ptl = huge_pte_lockptr(page_hstate(page), mm, pvmw->pte);
|
||||
- spin_lock(pvmw->ptl);
|
||||
- if (!check_pte(pvmw))
|
||||
- return not_found(pvmw);
|
||||
- return true;
|
||||
- }
|
||||
-restart:
|
||||
- pgd = pgd_offset(mm, pvmw->address);
|
||||
- if (!pgd_present(*pgd))
|
||||
- return false;
|
||||
- pud = pud_offset(pgd, pvmw->address);
|
||||
- if (!pud_present(*pud))
|
||||
- return false;
|
||||
- pvmw->pmd = pmd_offset(pud, pvmw->address);
|
||||
- if (pmd_trans_huge(*pvmw->pmd)) {
|
||||
- pvmw->ptl = pmd_lock(mm, pvmw->pmd);
|
||||
- if (!pmd_present(*pvmw->pmd))
|
||||
- return not_found(pvmw);
|
||||
- if (likely(pmd_trans_huge(*pvmw->pmd))) {
|
||||
- if (pvmw->flags & PVMW_MIGRATION)
|
||||
- return not_found(pvmw);
|
||||
- if (pmd_page(*pvmw->pmd) != page)
|
||||
- return not_found(pvmw);
|
||||
- return true;
|
||||
- } else {
|
||||
- /* THP pmd was split under us: handle on pte level */
|
||||
- spin_unlock(pvmw->ptl);
|
||||
- pvmw->ptl = NULL;
|
||||
- }
|
||||
- } else {
|
||||
- if (!check_pmd(pvmw))
|
||||
- return false;
|
||||
- }
|
||||
- if (!map_pte(pvmw))
|
||||
- goto next_pte;
|
||||
- while (1) {
|
||||
- if (check_pte(pvmw))
|
||||
- return true;
|
||||
-next_pte: do {
|
||||
- pvmw->address += PAGE_SIZE;
|
||||
- if (pvmw->address >=
|
||||
- __vma_address(pvmw->page, pvmw->vma) +
|
||||
- hpage_nr_pages(pvmw->page) * PAGE_SIZE)
|
||||
- return not_found(pvmw);
|
||||
- /* Did we cross page table boundary? */
|
||||
- if (pvmw->address % PMD_SIZE == 0) {
|
||||
- pte_unmap(pvmw->pte);
|
||||
- if (pvmw->ptl) {
|
||||
- spin_unlock(pvmw->ptl);
|
||||
- pvmw->ptl = NULL;
|
||||
- }
|
||||
- goto restart;
|
||||
- } else {
|
||||
- pvmw->pte++;
|
||||
- }
|
||||
- } while (pte_none(*pvmw->pte));
|
||||
-
|
||||
- if (!pvmw->ptl) {
|
||||
- pvmw->ptl = pte_lockptr(mm, pvmw->pmd);
|
||||
- spin_lock(pvmw->ptl);
|
||||
- }
|
||||
- }
|
||||
-}
|
||||
--
|
||||
2.7.4
|
||||
|
||||
|
|
@ -0,0 +1,77 @@
|
|||
From 361de9fb44163c4e693022786af380a2b2298c6d Mon Sep 17 00:00:00 2001
|
||||
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
|
||||
Date: Fri, 24 Feb 2017 14:59:19 -0800
|
||||
Subject: [PATCH 4/4] mm/ksm: handle protnone saved writes when making page
|
||||
write protect
|
||||
|
||||
Without this KSM will consider the page write protected, but a numa
|
||||
fault can later mark the page writable. This can result in memory
|
||||
corruption.
|
||||
|
||||
Link: http://lkml.kernel.org/r/1487498625-10891-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com
|
||||
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
|
||||
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||||
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||||
(backported from commit 595cd8f256d24face93b2722927ec9c980419c26)
|
||||
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
|
||||
---
|
||||
include/asm-generic/pgtable.h | 8 ++++++++
|
||||
mm/ksm.c | 9 +++++++--
|
||||
2 files changed, 15 insertions(+), 2 deletions(-)
|
||||
|
||||
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
|
||||
index b6f3a8a4b738..8c8ba48bef0b 100644
|
||||
--- a/include/asm-generic/pgtable.h
|
||||
+++ b/include/asm-generic/pgtable.h
|
||||
@@ -200,6 +200,10 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
|
||||
#define pte_mk_savedwrite pte_mkwrite
|
||||
#endif
|
||||
|
||||
+#ifndef pte_clear_savedwrite
|
||||
+#define pte_clear_savedwrite pte_wrprotect
|
||||
+#endif
|
||||
+
|
||||
#ifndef pmd_savedwrite
|
||||
#define pmd_savedwrite pmd_write
|
||||
#endif
|
||||
@@ -208,6 +212,10 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
|
||||
#define pmd_mk_savedwrite pmd_mkwrite
|
||||
#endif
|
||||
|
||||
+#ifndef pmd_clear_savedwrite
|
||||
+#define pmd_clear_savedwrite pmd_wrprotect
|
||||
+#endif
|
||||
+
|
||||
#ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
|
||||
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
||||
static inline void pmdp_set_wrprotect(struct mm_struct *mm,
|
||||
diff --git a/mm/ksm.c b/mm/ksm.c
|
||||
index fed4afd8293b..099dfa45d596 100644
|
||||
--- a/mm/ksm.c
|
||||
+++ b/mm/ksm.c
|
||||
@@ -878,7 +878,8 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
|
||||
if (!ptep)
|
||||
goto out_mn;
|
||||
|
||||
- if (pte_write(*ptep) || pte_dirty(*ptep)) {
|
||||
+ if (pte_write(*ptep) || pte_dirty(*ptep) ||
|
||||
+ (pte_protnone(*ptep) && pte_savedwrite(*ptep))) {
|
||||
pte_t entry;
|
||||
|
||||
swapped = PageSwapCache(page);
|
||||
@@ -903,7 +904,11 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
|
||||
}
|
||||
if (pte_dirty(entry))
|
||||
set_page_dirty(page);
|
||||
- entry = pte_mkclean(pte_wrprotect(entry));
|
||||
+
|
||||
+ if (pte_protnone(entry))
|
||||
+ entry = pte_mkclean(pte_clear_savedwrite(entry));
|
||||
+ else
|
||||
+ entry = pte_mkclean(pte_wrprotect(entry));
|
||||
set_pte_at_notify(mm, addr, ptep, entry);
|
||||
}
|
||||
*orig_pte = *ptep;
|
||||
--
|
||||
2.7.4
|
||||
|
||||
Loading…
Reference in a new issue