releases/4.9.135/mm-preserve-_page_devmap-across-mprotect-calls.patch

   1 From 4628a64591e6cee181237060961e98c615c33966 Mon Sep 17 00:00:00 2001
   2 From: Jan Kara <jack@suse.cz>
   3 Date: Tue, 9 Oct 2018 12:19:17 +0200
   4 Subject: mm: Preserve _PAGE_DEVMAP across mprotect() calls
   5
   6 From: Jan Kara <jack@suse.cz>
   7
   8 commit 4628a64591e6cee181237060961e98c615c33966 upstream.
   9
  10 Currently _PAGE_DEVMAP bit is not preserved in mprotect(2) calls. As a
  11 result we will see warnings such as:
  12
  13 BUG: Bad page map in process JobWrk0013  pte:800001803875ea25 pmd:7624381067
  14 addr:00007f0930720000 vm_flags:280000f9 anon_vma:          (null) mapping:ffff97f2384056f0 index:0
  15 file:457-000000fe00000030-00000009-000000ca-00000001_2001.fileblock fault:xfs_filemap_fault [xfs] mmap:xfs_file_mmap [xfs] readpage:          (null)
  16 CPU: 3 PID: 15848 Comm: JobWrk0013 Tainted: G        W          4.12.14-2.g7573215-default #1 SLE12-SP4 (unreleased)
  17 Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.01.00.0833.051120182255 05/11/2018
  18 Call Trace:
  19  dump_stack+0x5a/0x75
  20  print_bad_pte+0x217/0x2c0
  21  ? enqueue_task_fair+0x76/0x9f0
  22  _vm_normal_page+0xe5/0x100
  23  zap_pte_range+0x148/0x740
  24  unmap_page_range+0x39a/0x4b0
  25  unmap_vmas+0x42/0x90
  26  unmap_region+0x99/0xf0
  27  ? vma_gap_callbacks_rotate+0x1a/0x20
  28  do_munmap+0x255/0x3a0
  29  vm_munmap+0x54/0x80
  30  SyS_munmap+0x1d/0x30
  31  do_syscall_64+0x74/0x150
  32  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
  33 ...
  34
  35 when mprotect(2) gets used on DAX mappings. Also there is a wide variety
  36 of other failures that can result from the missing _PAGE_DEVMAP flag
  37 when the area gets used by get_user_pages() later.
  38
  39 Fix the problem by including _PAGE_DEVMAP in a set of flags that get
  40 preserved by mprotect(2).
  41
  42 Fixes: 69660fd797c3 ("x86, mm: introduce _PAGE_DEVMAP")
  43 Fixes: ebd31197931d ("powerpc/mm: Add devmap support for ppc64")
  44 Cc: <stable@vger.kernel.org>
  45 Signed-off-by: Jan Kara <jack@suse.cz>
  46 Acked-by: Michal Hocko <mhocko@suse.com>
  47 Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
  48 Signed-off-by: Dan Williams <dan.j.williams@intel.com>
  49 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  50
  51 ---
  52  arch/x86/include/asm/pgtable_types.h |    2 +-
  53  1 file changed, 1 insertion(+), 1 deletion(-)
  54
  55 --- a/arch/x86/include/asm/pgtable_types.h
  56 +++ b/arch/x86/include/asm/pgtable_types.h
  57 @@ -134,7 +134,7 @@
  58   */
  59  #define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT |         \
  60                          _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \
  61 -                        _PAGE_SOFT_DIRTY)
  62 +                        _PAGE_SOFT_DIRTY | _PAGE_DEVMAP)
  63  #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
  64
  65  /* The ASID is the lower 12 bits of CR3 */