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| author | Youquan Song <youquan.song@intel.com> | 2011-12-08 14:34:18 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-12-09 07:50:28 -0800 |
| commit | 58a84aa92723d1ac3e1cc4e3b0ff49291663f7e1 (patch) | |
| tree | bdfad6b0f38590318da0dee67ff84718b60a8ca5 /mm/pgtable-generic.c | |
| parent | b6999b19120931ede364fa3b685e698a61fed31d (diff) | |
| download | op-kernel-dev-58a84aa92723d1ac3e1cc4e3b0ff49291663f7e1.zip op-kernel-dev-58a84aa92723d1ac3e1cc4e3b0ff49291663f7e1.tar.gz | |
thp: set compound tail page _count to zero
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 <youquan.song@intel.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/pgtable-generic.c')
0 files changed, 0 insertions, 0 deletions
