mm: numa: do not clear PTE for pte_numa update (0c5f83c2) · Commits · 戴 / test

The TLB must be flushed if the PTE is updated but change_pte_range is clearing the PTE while marking PTEs pte_numa without necessarily flushing the TLB if it reinserts the same entry. Without the flush, it's conceivable that two processors have different TLBs for the same virtual address and at the very least it would generate spurious faults. This patch only unmaps the pages in change_pte_range for a full protection change. [riel@redhat.com: write pte_numa pte back to the page tables] Signed-off-by:

Mel Gorman <mgorman@suse.de> Signed-off-by:

Rik van Riel <riel@redhat.com> Reviewed-by:

Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: Chegu Vinod <chegu_vinod@hp.com> Cc: <stable@vger.kernel.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/mprotect.c

+7 −2

Original line number	Original line	Diff line number	Diff line
	@@ -52,17 +52,19 @@ static unsigned long change_pte_range(struct vm_area_struct vma, pmd_t pmd,
	pte_t ptent;		pte_t ptent;
	bool updated = false;		bool updated = false;

	ptent = ptep_modify_prot_start(mm, addr, pte);
	if (!prot_numa) {		if (!prot_numa) {
			ptent = ptep_modify_prot_start(mm, addr, pte);
	ptent = pte_modify(ptent, newprot);		ptent = pte_modify(ptent, newprot);
	updated = true;		updated = true;
	} else {		} else {
	struct page *page;		struct page *page;

			ptent = *pte;
	page = vm_normal_page(vma, addr, oldpte);		page = vm_normal_page(vma, addr, oldpte);
	if (page) {		if (page) {
	if (!pte_numa(oldpte)) {		if (!pte_numa(oldpte)) {
	ptent = pte_mknuma(ptent);		ptent = pte_mknuma(ptent);
			set_pte_at(mm, addr, pte, ptent);
	updated = true;		updated = true;
	}		}
	}		}
	@@ -79,6 +81,9 @@ static unsigned long change_pte_range(struct vm_area_struct vma, pmd_t pmd,

	if (updated)		if (updated)
	pages++;		pages++;

			/* Only !prot_numa always clears the pte */
			if (!prot_numa)
	ptep_modify_prot_commit(mm, addr, pte, ptent);		ptep_modify_prot_commit(mm, addr, pte, ptent);
	} else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) {		} else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) {
	swp_entry_t entry = pte_to_swp_entry(oldpte);		swp_entry_t entry = pte_to_swp_entry(oldpte);

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