Re: [PATCH] KVM: page_track: fix access to NULL slot

[Xiao Guangrong]

On 03/23/2016 12:40 AM, Paolo Bonzini wrote:
> This happens when doing the reboot test from virt-tests:
>
> [  131.833653] BUG: unable to handle kernel NULL pointer dereference at           (null)
> [  131.842461] IP: [<ffffffffa0950087>] kvm_page_track_is_active+0x17/0x60 [kvm]
> [  131.850500] PGD 0
> [  131.852763] Oops: 0000 [#1] SMP
> [  132.007188] task: ffff880075fbc500 ti: ffff880850a3c000 task.ti: ffff880850a3c000
> [  132.138891] Call Trace:
> [  132.141639]  [<ffffffffa092bd11>] page_fault_handle_page_track+0x31/0x40 [kvm]
> [  132.149732]  [<ffffffffa093380f>] paging64_page_fault+0xff/0x910 [kvm]
> [  132.172159]  [<ffffffffa092c734>] kvm_mmu_page_fault+0x64/0x110 [kvm]
> [  132.179372]  [<ffffffffa06743c2>] handle_exception+0x1b2/0x430 [kvm_intel]
> [  132.187072]  [<ffffffffa067a301>] vmx_handle_exit+0x1e1/0xc50 [kvm_intel]
> ...

Thank you for fixing it, Paolo!

Reviewed-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>