From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:36860 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753623AbdLDIsh (ORCPT ); Mon, 4 Dec 2017 03:48:37 -0500 Subject: Patch "mm: fix device-dax pud write-faults triggered by get_user_pages()" has been added to the 4.14-stable tree To: dan.j.williams@intel.com, akpm@linux-foundation.org, arnd@arndb.de, catalin.marinas@arm.com, dave.hansen@intel.com, davem@davemloft.net, gregkh@linuxfoundation.org, hpa@zytor.com, kirill.shutemov@linux.intel.com, mingo@redhat.com, sfr@canb.auug.org.au, tglx@linutronix.de, torvalds@linux-foundation.org, will.deacon@arm.com Cc: , From: Date: Mon, 04 Dec 2017 09:48:36 +0100 Message-ID: <151237731693147@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled mm: fix device-dax pud write-faults triggered by get_user_pages() to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-fix-device-dax-pud-write-faults-triggered-by-get_user_pages.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 1501899a898dfb5477c55534bdfd734c046da06d Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 29 Nov 2017 16:10:06 -0800 Subject: mm: fix device-dax pud write-faults triggered by get_user_pages() From: Dan Williams commit 1501899a898dfb5477c55534bdfd734c046da06d upstream. Currently only get_user_pages_fast() can safely handle the writable gup case due to its use of pud_access_permitted() to check whether the pud entry is writable. In the gup slow path pud_write() is used instead of pud_access_permitted() and to date it has been unimplemented, just calls BUG_ON(). kernel BUG at ./include/linux/hugetlb.h:244! [..] RIP: 0010:follow_devmap_pud+0x482/0x490 [..] Call Trace: follow_page_mask+0x28c/0x6e0 __get_user_pages+0xe4/0x6c0 get_user_pages_unlocked+0x130/0x1b0 get_user_pages_fast+0x89/0xb0 iov_iter_get_pages_alloc+0x114/0x4a0 nfs_direct_read_schedule_iovec+0xd2/0x350 ? nfs_start_io_direct+0x63/0x70 nfs_file_direct_read+0x1e0/0x250 nfs_file_read+0x90/0xc0 For now this just implements a simple check for the _PAGE_RW bit similar to pmd_write. However, this implies that the gup-slow-path check is missing the extra checks that the gup-fast-path performs with pud_access_permitted. Later patches will align all checks to use the 'access_permitted' helper if the architecture provides it. Note that the generic 'access_permitted' helper fallback is the simple _PAGE_RW check on architectures that do not define the 'access_permitted' helper(s). [dan.j.williams@intel.com: fix powerpc compile error] Link: http://lkml.kernel.org/r/151129126165.37405.16031785266675461397.stgit@dwillia2-desk3.amr.corp.intel.com Link: http://lkml.kernel.org/r/151043109938.2842.14834662818213616199.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: a00cc7d9dd93 ("mm, x86: add support for PUD-sized transparent hugepages") Signed-off-by: Dan Williams Reported-by: Stephen Rothwell Acked-by: Thomas Gleixner [x86] Cc: Kirill A. Shutemov Cc: Catalin Marinas Cc: "David S. Miller" Cc: Dave Hansen Cc: Will Deacon Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/pgtable.h | 6 ++++++ include/asm-generic/pgtable.h | 8 ++++++++ include/linux/hugetlb.h | 8 -------- 3 files changed, 14 insertions(+), 8 deletions(-) --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -1093,6 +1093,12 @@ static inline void pmdp_set_wrprotect(st clear_bit(_PAGE_BIT_RW, (unsigned long *)pmdp); } +#define pud_write pud_write +static inline int pud_write(pud_t pud) +{ + return pud_flags(pud) & _PAGE_RW; +} + /* * clone_pgd_range(pgd_t *dst, pgd_t *src, int count); * --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -814,6 +814,14 @@ static inline int pmd_write(pmd_t pmd) #endif /* __HAVE_ARCH_PMD_WRITE */ #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ +#ifndef pud_write +static inline int pud_write(pud_t pud) +{ + BUG(); + return 0; +} +#endif /* pud_write */ + #if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \ (defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)) --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -239,14 +239,6 @@ static inline int pgd_write(pgd_t pgd) } #endif -#ifndef pud_write -static inline int pud_write(pud_t pud) -{ - BUG(); - return 0; -} -#endif - #define HUGETLB_ANON_FILE "anon_hugepage" enum { Patches currently in stable-queue which might be from dan.j.williams@intel.com are queue-4.14/mm-hugetlbfs-introduce-split-to-vm_operations_struct.patch queue-4.14/ib-core-disable-memory-registration-of-filesystem-dax-vmas.patch queue-4.14/mm-introduce-get_user_pages_longterm.patch queue-4.14/mm-fail-get_vaddr_frames-for-filesystem-dax-mappings.patch queue-4.14/device-dax-implement-split-to-catch-invalid-munmap-attempts.patch queue-4.14/v4l2-disable-filesystem-dax-mapping-support.patch queue-4.14/mm-fix-device-dax-pud-write-faults-triggered-by-get_user_pages.patch queue-4.14/mm-madvise.c-fix-madvise-infinite-loop-under-special-circumstances.patch