path: root/kernel
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authorYouquan Song <>2011-12-08 14:34:18 -0800
committerGreg Kroah-Hartman <>2011-12-21 12:58:22 -0800
commit7f37071e9df2344a7d7d066235ec72a0d1a4b013 (patch)
tree159499fa82f3aa12ee6539c7f5f7d5d507d693f8 /kernel
parent75aaef5468ceb118aa55825cf6a52d60d09dfde0 (diff)
thp: set compound tail page _count to zero
commit 58a84aa92723d1ac3e1cc4e3b0ff49291663f7e1 upstream. Commit 70b50f94f1644 ("mm: thp: tail page refcounting fix") keeps all page_tail->_count zero at all times. But the current kernel does not set page_tail->_count to zero if a 1GB page is utilized. So when an IOMMU 1GB page is used by KVM, it wil result in a kernel oops because a tail page's _count does not equal zero. kernel BUG at include/linux/mm.h:386! invalid opcode: 0000 [#1] SMP Call Trace: gup_pud_range+0xb8/0x19d get_user_pages_fast+0xcb/0x192 ? trace_hardirqs_off+0xd/0xf hva_to_pfn+0x119/0x2f2 gfn_to_pfn_memslot+0x2c/0x2e kvm_iommu_map_pages+0xfd/0x1c1 kvm_iommu_map_memslots+0x7c/0xbd kvm_iommu_map_guest+0xaa/0xbf kvm_vm_ioctl_assigned_device+0x2ef/0xa47 kvm_vm_ioctl+0x36c/0x3a2 do_vfs_ioctl+0x49e/0x4e4 sys_ioctl+0x5a/0x7c system_call_fastpath+0x16/0x1b RIP gup_huge_pud+0xf2/0x159 Signed-off-by: Youquan Song <> Reviewed-by: Andrea Arcangeli <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <> Signed-off-by: Greg Kroah-Hartman <>
Diffstat (limited to 'kernel')
0 files changed, 0 insertions, 0 deletions