On Tue, Mar 31, 2015 at 03:01:58PM +0200, Christian Borntraeger wrote:
> From: Jens Freimann <jfrei@xxxxxxxxxxxxxxxxxx>
>
> This fixes a bug introduced with commit c05c4186bbe4 ("KVM: s390:
> add floating irq controller").
>
> get_all_floating_irqs() does copy_to_user() while holding
> a spin lock. Let's fix this by filling a temporary buffer
> first and copy it to userspace after giving up the lock.
>
> Cc: <stable@xxxxxxxxxxxxxxx> # 3.18+: 69a8d4562638 KVM: s390: no need to hold...
>
> Reviewed-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Jens Freimann <jfrei@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> Acked-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
...
> -static int get_all_floating_irqs(struct kvm *kvm, __u8 *buf, __u64 len)
> +static int get_all_floating_irqs(struct kvm *kvm, __user u8 *usrbuf, u64 len)
fwiw, this is probably the only place within the kernel where we see
"__user u8 *" instead of "u8 __user *". This is odd within this whole
patch.
> + if (copy_to_user((void __user *) usrbuf,
The cast shouldn't be necessary at all...
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