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authorReza Arbab <arbab@linux.vnet.ibm.com>2017-10-03 16:15:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-10-03 17:54:25 -0700
commit7d790d2da386a52cfebcf0c898ba927bece9d4ab (patch)
tree90d5ebc5d441594d88195fe352b56036c718644a /mm/memory.c
parent9625456cc76391b7f3f2809579126542a8ed4d39 (diff)
downloadlinux-7d790d2da386a52cfebcf0c898ba927bece9d4ab.tar.gz
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: df6ad69838fc ("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>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c
index ec4e15494901..a728bed16c20 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -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)) {