Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754737AbaBGMB6 (ORCPT ); Fri, 7 Feb 2014 07:01:58 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:42450 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754041AbaBGLw3 (ORCPT ); Fri, 7 Feb 2014 06:52:29 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Aneesh Kumar K.V" , Benjamin Herrenschmidt , Luis Henriques Subject: [PATCH 3.11 208/233] powerpc: thp: Fix crash on mremap Date: Fri, 7 Feb 2014 11:47:07 +0000 Message-Id: <1391773652-25214-209-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1391773652-25214-1-git-send-email-luis.henriques@canonical.com> References: <1391773652-25214-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "Aneesh Kumar K.V" commit b3084f4db3aeb991c507ca774337c7e7893ed04f upstream. This patch fix the below crash NIP [c00000000004cee4] .__hash_page_thp+0x2a4/0x440 LR [c0000000000439ac] .hash_page+0x18c/0x5e0 ... Call Trace: [c000000736103c40] [00001ffffb000000] 0x1ffffb000000(unreliable) [437908.479693] [c000000736103d50] [c0000000000439ac] .hash_page+0x18c/0x5e0 [437908.479699] [c000000736103e30] [c00000000000924c] .do_hash_page+0x4c/0x58 On ppc64 we use the pgtable for storing the hpte slot information and store address to the pgtable at a constant offset (PTRS_PER_PMD) from pmd. On mremap, when we switch the pmd, we need to withdraw and deposit the pgtable again, so that we find the pgtable at PTRS_PER_PMD offset from new pmd. We also want to move the withdraw and deposit before the set_pmd so that, when page fault find the pmd as trans huge we can be sure that pgtable can be located at the offset. Signed-off-by: Aneesh Kumar K.V Cc: Benjamin Herrenschmidt [ aneesh: variant of upstream SHA1: b3084f4db3aeb991c507ca774337c7e7893ed04f for 3.11 stable series ] Signed-off-by: Luis Henriques --- arch/Kconfig | 3 +++ arch/powerpc/platforms/Kconfig.cputype | 1 + mm/huge_memory.c | 12 ++++++++++++ 3 files changed, 16 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index 1feb169..c5863b3 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -368,6 +368,9 @@ config HAVE_ARCH_TRANSPARENT_HUGEPAGE config HAVE_ARCH_SOFT_DIRTY bool +config ARCH_THP_MOVE_PMD_ALWAYS_WITHDRAW + bool + config HAVE_MOD_ARCH_SPECIFIC bool help diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index 47d9a03..d11a34b 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -71,6 +71,7 @@ config PPC_BOOK3S_64 select PPC_FPU select PPC_HAVE_PMU_SUPPORT select SYS_SUPPORTS_HUGETLBFS + select ARCH_THP_MOVE_PMD_ALWAYS_WITHDRAW select HAVE_ARCH_TRANSPARENT_HUGEPAGE if PPC_64K_PAGES config PPC_BOOK3E_64 diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 5e91a87..46a02bf 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1486,8 +1486,20 @@ int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, ret = __pmd_trans_huge_lock(old_pmd, vma); if (ret == 1) { +#ifdef CONFIG_ARCH_THP_MOVE_PMD_ALWAYS_WITHDRAW + pgtable_t pgtable; +#endif pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); VM_BUG_ON(!pmd_none(*new_pmd)); +#ifdef CONFIG_ARCH_THP_MOVE_PMD_ALWAYS_WITHDRAW + /* + * Archs like ppc64 use pgtable to store per pmd + * specific information. So when we switch the pmd, + * we should also withdraw and deposit the pgtable + */ + pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); + pgtable_trans_huge_deposit(mm, new_pmd, pgtable); +#endif set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); spin_unlock(&mm->page_table_lock); } -- 1.8.3.2 -- 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/