Youquan Song b6999b1912 thp: add compound tail page _mapcount when mapped ... With the 3.2-rc kernel, IOMMU 2M pages in KVM works. But when I tried to use IOMMU 1GB pages in KVM, I encountered an oops and the 1GB page failed to be used. The root cause is that 1GB page allocation calls gup_huge_pud() while 2M page calls gup_huge_pmd. If compound pages are used and the page is a tail page, gup_huge_pmd() increases _mapcount to record tail page are mapped while gup_huge_pud does not do that. So when the mapped page is relesed, it will result in kernel oops because the page is not marked mapped. This patch add tail process for compound page in 1GB huge page which keeps the same process as 2M page. Reproduce like: 1. Add grub boot option: hugepagesz=1G hugepages=8 2. mount -t hugetlbfs -o pagesize=1G hugetlbfs /dev/hugepages 3. qemu-kvm -m 2048 -hda os-kvm.img -cpu kvm64 -smp 4 -mem-path /dev/hugepages -net none -device pci-assign,host=07:00.1 kernel BUG at mm/swap.c:114! invalid opcode: 0000 [#1] SMP Call Trace: put_page+0x15/0x37 kvm_release_pfn_clean+0x31/0x36 kvm_iommu_put_pages+0x94/0xb1 kvm_iommu_unmap_memslots+0x80/0xb6 kvm_assign_device+0xba/0x117 kvm_vm_ioctl_assigned_device+0x301/0xa47 kvm_vm_ioctl+0x36c/0x3a2 do_vfs_ioctl+0x49e/0x4e4 sys_ioctl+0x5a/0x7c system_call_fastpath+0x16/0x1b RIP put_compound_page+0xd4/0x168 Signed-off-by: Youquan Song <youquan.song@intel.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2011-12-09 07:50:28 -08:00
..
kmemcheck	x86: Swap save_stack_trace_regs parameters	2011-06-14 22:48:51 -04:00
amdtopology.c
dump_pagetables.c
extable.c
fault.c	Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2011-10-28 05:46:02 -07:00
gup.c	thp: add compound tail page _mapcount when mapped	2011-12-09 07:50:28 -08:00
highmem_32.c	x86/paravirt: PTE updates in k(un)map_atomic need to be synchronous, regardless of lazy_mmu mode	2011-12-05 17:06:34 +01:00
hugetlbpage.c	mm: Convert i_mmap_lock to a mutex	2011-05-25 08:39:18 -07:00
init_32.c
init_64.c	mm: Move definition of MIN_MEMORY_BLOCK_SIZE to a header	2011-07-12 11:08:01 +10:00
init.c	x86: Fix S4 regression	2011-10-24 06:55:20 +02:00
iomap_32.c
ioremap.c
kmmio.c
Makefile
memblock.c	x86, efi: Do not reserve boot services regions within reserved areas	2011-06-18 22:48:49 +02:00
memtest.c
mmap.c	x86-32, amd: Move va_align definition to unbreak 32-bit build	2011-08-06 11:44:57 -07:00
mmio-mod.c	Merge branch 'master' into for-next	2011-09-15 15:08:18 +02:00
numa_32.c	x86, mm: s/PAGES_PER_ELEMENT/PAGES_PER_SECTION/	2011-07-12 21:58:11 -07:00
numa_64.c
numa_emulation.c
numa_internal.h
numa.c	x86, numa: Implement pfn -> nid mapping granularity check	2011-07-12 21:58:29 -07:00
pageattr-test.c	x86: Convert vmalloc()+memset() to vzalloc()	2011-05-28 19:53:57 +02:00
pageattr.c
pat_internal.h
pat_rbtree.c
pat.c
pf_in.c	x86: Eliminate various 'set but not used' warnings	2011-05-21 19:10:33 +02:00
pf_in.h
pgtable_32.c
pgtable.c
physaddr.c
physaddr.h
setup_nx.c
srat.c
testmmiotrace.c
tlb.c