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| author | Jia He <hejianet@gmail.com> | 2018-05-21 11:05:30 +0800 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2018-06-21 11:48:03 +0100 |
| commit | 47a91b7232fa25abc7e0b7fc1c69ae4f81061594 (patch) | |
| tree | b5cf4dc98c939e68cd2d4ff5e3675fe7be62e6ca /virt/kvm/arm/mmu.c | |
| parent | 2955bcc8c309bb8f2c773db4798649aa802a491f (diff) | |
| download | linux-47a91b7232fa25abc7e0b7fc1c69ae4f81061594.tar.bz2 | |
KVM: arm/arm64: add WARN_ON if size is not PAGE_SIZE aligned in unmap_stage2_range
There is a panic in armv8a server(QDF2400) under memory pressure tests
(start 20 guests and run memhog in the host).
---------------------------------begin--------------------------------
[35380.800950] BUG: Bad page state in process qemu-kvm pfn:dd0b6
[35380.805825] page:ffff7fe003742d80 count:-4871 mapcount:-2126053375
mapping: (null) index:0x0
[35380.815024] flags: 0x1fffc00000000000()
[35380.818845] raw: 1fffc00000000000 0000000000000000 0000000000000000
ffffecf981470000
[35380.826569] raw: dead000000000100 dead000000000200 ffff8017c001c000
0000000000000000
[35380.805825] page:ffff7fe003742d80 count:-4871 mapcount:-2126053375
mapping: (null) index:0x0
[35380.815024] flags: 0x1fffc00000000000()
[35380.818845] raw: 1fffc00000000000 0000000000000000 0000000000000000
ffffecf981470000
[35380.826569] raw: dead000000000100 dead000000000200 ffff8017c001c000
0000000000000000
[35380.834294] page dumped because: nonzero _refcount
[...]
--------------------------------end--------------------------------------
The root cause might be what was fixed at [1]. But from the KVM points of
view, it would be better if the issue was caught earlier.
If the size is not PAGE_SIZE aligned, unmap_stage2_range might unmap the
wrong(more or less) page range. Hence it caused the "BUG: Bad page
state"
Let's WARN in that case, so that the issue is obvious.
[1] https://lkml.org/lkml/2018/5/3/1042
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: jia.he@hxt-semitech.com
[maz: tidied up commit message]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'virt/kvm/arm/mmu.c')
| -rw-r--r-- | virt/kvm/arm/mmu.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 8d90de213ce9..1d90d79706bd 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -297,6 +297,8 @@ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size) phys_addr_t next; assert_spin_locked(&kvm->mmu_lock); + WARN_ON(size & ~PAGE_MASK); + pgd = kvm->arch.pgd + stage2_pgd_index(addr); do { /* |