Re: [PATCH v1] KVM: Use memdup_user instead of kernel stack to allocate kvm_guest_debug

[Leesoo Ahn]

Bump up the patch in order to remind again.

2026년 2월 10일 (화) PM 4:25, Leesoo Ahn <lsahn@xxxxxxxxxx>님이 작성:
>
> Switch to using memdup_user to allocate its memory because the size of
> kvm_guest_debug is over 512 bytes on Arm64 and is burdened allocation
> from kernel stack.
>
> Signed-off-by: Leesoo Ahn <lsahn@xxxxxxxxxx>
> ---
>  virt/kvm/kvm_main.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 5b5b69c97665..bc0a53129df7 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -4592,12 +4592,15 @@ static long kvm_vcpu_ioctl(struct file *filp,
>                 break;
>         }
>         case KVM_SET_GUEST_DEBUG: {
> -               struct kvm_guest_debug dbg;
> +               struct kvm_guest_debug *dbg;
>
> -               r = -EFAULT;
> -               if (copy_from_user(&dbg, argp, sizeof(dbg)))
> +               dbg = memdup_user(argp, sizeof(*dbg));
> +               if (IS_ERR(dbg)) {
> +                       r = PTR_ERR(dbg);
>                         goto out;
> -               r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg);
> +               }
> +               r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, dbg);
> +               kfree(dbg);
>                 break;
>         }
>         case KVM_SET_SIGNAL_MASK: {
> --
> 2.51.0
>