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authorJia He <hejianet@gmail.com>2018-05-21 06:05:30 +0300
committerMarc Zyngier <marc.zyngier@arm.com>2018-06-21 13:48:03 +0300
commit47a91b7232fa25abc7e0b7fc1c69ae4f81061594 (patch)
treeb5cf4dc98c939e68cd2d4ff5e3675fe7be62e6ca /virt
parent2955bcc8c309bb8f2c773db4798649aa802a491f (diff)
downloadlinux-47a91b7232fa25abc7e0b7fc1c69ae4f81061594.tar.xz
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')
-rw-r--r--virt/kvm/arm/mmu.c2
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 {
/*