Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934172AbbFPJeI (ORCPT ); Tue, 16 Jun 2015 05:34:08 -0400 Received: from mail.kernel.org ([198.145.29.136]:54511 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752563AbbFPIlX (ORCPT ); Tue, 16 Jun 2015 04:41:23 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Naoya Horiguchi , Hugh Dickins , James Hogan , David Rientjes , Mel Gorman , Johannes Weiner , Michal Hocko , Rik van Riel , Andrea Arcangeli , Luiz Capitulino , Nishanth Aravamudan , Lee Schermerhorn , Steve Capper , Andrew Morton , Linus Torvalds , Zefan Li Subject: [PATCH 3.4 028/172] mm/hugetlb: add migration/hwpoisoned entry check in hugetlb_change_protection Date: Tue, 16 Jun 2015 16:34:42 +0800 Message-Id: <1434443826-4929-28-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1434443587-4599-1-git-send-email-lizf@kernel.org> References: <1434443587-4599-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2684 Lines: 78 From: Naoya Horiguchi 3.4.108-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit a8bda28d87c38c6aa93de28ba5d30cc18e865a11 upstream. There is a race condition between hugepage migration and change_protection(), where hugetlb_change_protection() doesn't care about migration entries and wrongly overwrites them. That causes unexpected results like kernel crash. HWPoison entries also can cause the same problem. This patch adds is_hugetlb_entry_(migration|hwpoisoned) check in this function to do proper actions. Fixes: 290408d4a2 ("hugetlb: hugepage migration core") Signed-off-by: Naoya Horiguchi Cc: Hugh Dickins Cc: James Hogan Cc: David Rientjes Cc: Mel Gorman Cc: Johannes Weiner Cc: Michal Hocko Cc: Rik van Riel Cc: Andrea Arcangeli Cc: Luiz Capitulino Cc: Nishanth Aravamudan Cc: Lee Schermerhorn Cc: Steve Capper Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [lizf: Backported to 3.4: - remove locking of ptl - remove counting of pages] Signed-off-by: Zefan Li --- mm/hugetlb.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index d02fbbc..5f12dba 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3052,7 +3052,22 @@ void hugetlb_change_protection(struct vm_area_struct *vma, continue; if (huge_pmd_unshare(mm, &address, ptep)) continue; - if (!huge_pte_none(huge_ptep_get(ptep))) { + pte = huge_ptep_get(ptep); + if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) + continue; + if (unlikely(is_hugetlb_entry_migration(pte))) { + swp_entry_t entry = pte_to_swp_entry(pte); + + if (is_write_migration_entry(entry)) { + pte_t newpte; + + make_migration_entry_read(&entry); + newpte = swp_entry_to_pte(entry); + set_huge_pte_at(mm, address, ptep, newpte); + } + continue; + } + if (!huge_pte_none(pte)) { pte = huge_ptep_get_and_clear(mm, address, ptep); pte = pte_mkhuge(pte_modify(pte, newprot)); set_huge_pte_at(mm, address, ptep, pte); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/