• Paolo Bonzini's avatar
    KVM: fix spin_lock_init order on x86 · 4e2fa4bb
    Paolo Bonzini authored
    commit e9ad4ec8 upstream.
    
    Moving the initialization earlier is needed in 4.6 because
    kvm_arch_init_vm is now using mmu_lock, causing lockdep to
    complain:
    
    [  284.440294] INFO: trying to register non-static key.
    [  284.445259] the code is fine but needs lockdep annotation.
    [  284.450736] turning off the locking correctness validator.
    ...
    [  284.528318]  [<ffffffff810aecc3>] lock_acquire+0xd3/0x240
    [  284.533733]  [<ffffffffa0305aa0>] ? kvm_page_track_register_notifier+0x20/0x60 [kvm]
    [  284.541467]  [<ffffffff81715581>] _raw_spin_lock+0x41/0x80
    [  284.546960]  [<ffffffffa0305aa0>] ? kvm_page_track_register_notifier+0x20/0x60 [kvm]
    [  284.554707]  [<ffffffffa0305aa0>] kvm_page_track_register_notifier+0x20/0x60 [kvm]
    [  284.562281]  [<ffffffffa02ece70>] kvm_mmu_init_vm+0x20/0x30 [kvm]
    [  284.568381]  [<ffffffffa02dbf7a>] kvm_arch_init_vm+0x1ea/0x200 [kvm]
    [  284.574740]  [<ffffffffa02bff3f>] kvm_dev_ioctl+0xbf/0x4d0 [kvm]
    
    However, it also helps fixing a preexisting problem, which is why this
    patch is also good for stable kernels: kvm_create_vm was incrementing
    current->mm->mm_count but not decrementing it at the out_err label (in
    case kvm_init_mmu_notifier failed).  The new initialization order makes
    it possible to add the required mmdrop without adding a new error label.
    Reported-by: default avatarBorislav Petkov <bp@alien8.de>
    Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    4e2fa4bb
kvm_main.c 84.2 KB