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: df6ad698 ("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>
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