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mm/device-public-memory: fix edge case in _vm_normal_page() 

With device public pages at the end of my memory space, I'm getting
output from _vm_normal_page():

  BUG: Bad page map in process migrate_pages  pte:c0800001ffff0d06 pmd:f95d3000
  addr:00007fff89330000 vm_flags:00100073 anon_vma:c0000000fa899320 mapping:          (null) index:7fff8933
  file:          (null) fault:          (null) mmap:          (null) readpage:          (null)
  CPU: 0 PID: 13963 Comm: migrate_pages Tainted: P    B      OE 4.14.0-rc1-wip #155
  Call Trace:
     dump_stack+0xb0/0xf4 (unreliable)
     print_bad_pte+0x28c/0x340
     _vm_normal_page+0xc0/0x140
     zap_pte_range+0x664/0xc10
     unmap_page_range+0x318/0x670
     unmap_vmas+0x74/0xe0
     exit_mmap+0xe8/0x1f0
     mmput+0xac/0x1f0
     do_exit+0x348/0xcd0
     do_group_exit+0x5c/0xf0
     SyS_exit_group+0x1c/0x20
     system_call+0x58/0x6c

The pfn causing this is the very last one.  Correct the bounds check
accordingly.

Fixes: df6ad69838 ("mm/device-public-memory: device memory cache coherent with CPU")
Link: http://lkml.kernel.org/r/1506092178-20351-1-git-send-email-arbab@linux.vnet.ibm.com
Signed-off-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Reza Arbab 2017-10-03 16:15:35 -07:00 committed by Linus Torvalds
parent 9625456cc7
commit 7d790d2da3
1 changed files with 1 additions and 1 deletions
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2
mm/memory.c
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@ -845,7 +845,7 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
* vm_normal_page() so that we do not have to special case all
* call site of vm_normal_page().
*/
if (likely(pfn < highest_memmap_pfn)) {
if (likely(pfn <= highest_memmap_pfn)) {
struct page *page = pfn_to_page(pfn);
if (is_device_public_page(page)) {