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SubjectRe: [PATCH] arm, kvm: fix double lock on cpu_add_remove_lock
On 04/06/2014 11:06 PM, Ming Lei wrote:
> The patch of "arm, kvm: Fix CPU hotplug callback registration"
> in -next tree holds the lock before calling the two functions:
>
> kvm_vgic_hyp_init()
> kvm_timer_hyp_init()
>
> and both the two functions are calling register_cpu_notifier()
> to register cpu notifier, so cause double lock on cpu_add_remove_lock.
>
> Considered that both two functions are only called inside
> kvm_arch_init() with holding cpu_add_remove_lock, so simply use
> __register_cpu_notifier() to fix the problem.
>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Christoffer Dall <christoffer.dall@linaro.org>
> Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Ming Lei <tom.leiming@gmail.com>

Sorry for missing that, and thank you for the fix!

Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>

Regards,
Srivatsa S. Bhat

> ---
> virt/kvm/arm/arch_timer.c | 2 +-
> virt/kvm/arm/vgic.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
> index 5081e80..22fa819 100644
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@ -277,7 +277,7 @@ int kvm_timer_hyp_init(void)
>
> host_vtimer_irq = ppi;
>
> - err = register_cpu_notifier(&kvm_timer_cpu_nb);
> + err = __register_cpu_notifier(&kvm_timer_cpu_nb);
> if (err) {
> kvm_err("Cannot register timer CPU notifier\n");
> goto out_free;
> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
> index 8ca405c..47b2983 100644
> --- a/virt/kvm/arm/vgic.c
> +++ b/virt/kvm/arm/vgic.c
> @@ -1496,7 +1496,7 @@ int kvm_vgic_hyp_init(void)
> goto out;
> }
>
> - ret = register_cpu_notifier(&vgic_cpu_nb);
> + ret = __register_cpu_notifier(&vgic_cpu_nb);
> if (ret) {
> kvm_err("Cannot register vgic CPU notifier\n");
> goto out_free_irq;
>



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