linux-kernel - Re: [PATCH 4/4] KVM: nVMX: Fix using __this_cpu

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Date:   Fri, 17 May 2019 13:12:41 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Wanpeng Li <kernellwp@...il.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Subject: Re: [PATCH 4/4] KVM: nVMX: Fix using __this_cpu_read() in
 preemptible context

On Fri, May 17, 2019 at 04:49:50PM +0800, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@...cent.com>
> 
>  BUG: using __this_cpu_read() in preemptible [00000000] code: qemu-system-x86/4590
>   caller is nested_vmx_enter_non_root_mode+0xebd/0x1790 [kvm_intel]
>   CPU: 4 PID: 4590 Comm: qemu-system-x86 Tainted: G           OE     5.1.0-rc4+ #1
>   Call Trace:
>    dump_stack+0x67/0x95
>    __this_cpu_preempt_check+0xd2/0xe0
>    nested_vmx_enter_non_root_mode+0xebd/0x1790 [kvm_intel]
>    nested_vmx_run+0xda/0x2b0 [kvm_intel]
>    handle_vmlaunch+0x13/0x20 [kvm_intel]
>    vmx_handle_exit+0xbd/0x660 [kvm_intel]
>    kvm_arch_vcpu_ioctl_run+0xa2c/0x1e50 [kvm]
>    kvm_vcpu_ioctl+0x3ad/0x6d0 [kvm]
>    do_vfs_ioctl+0xa5/0x6e0
>    ksys_ioctl+0x6d/0x80
>    __x64_sys_ioctl+0x1a/0x20
>    do_syscall_64+0x6f/0x6c0
>    entry_SYSCALL_64_after_hwframe+0x49/0xbe
> 
> Accessing per-cpu variable should disable preemption, this patch extends the 
> preemption disable region for __this_cpu_read().
> 
> Cc: Paolo Bonzini <pbonzini@...hat.com>
> Cc: Radim Krčmář <rkrcmar@...hat.com>
> Signed-off-by: Wanpeng Li <wanpengli@...cent.com>
> ---

Fixes: 52017608da33 ("KVM: nVMX: add option to perform early consistency checks via H/W")

and probably

Cc: stable@...r.kernel.org

Reviewed-by: Sean Christopherson <sean.j.christopherson@...el.com>