2021-06-21 12:46:01

by Eric Auger

Subject: [PATCH for-stable-5.4] KVM: arm/arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST read

When reading the base address of the a REDIST region
through KVM_VGIC_V3_ADDR_TYPE_REDIST we expect the
redistributor region list to be populated with a single
element.

However list_first_entry() expects the list to be non empty.
Instead we should use list_first_entry_or_null which effectively
returns NULL if the list is empty.

Fixes: dbd9733ab674 ("KVM: arm/arm64: Replace the single rdist region by a list")
Cc: <[email protected]> # v5.4
Signed-off-by: Eric Auger <[email protected]>
Reported-by: Gavin Shan <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
virt/kvm/arm/vgic/vgic-kvm-device.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
index 44419679f91a..5eaede3e3b5a 100644
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
@@ -87,8 +87,8 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
r = vgic_v3_set_redist_base(kvm, 0, *addr, 0);
goto out;
}
- rdreg = list_first_entry(&vgic->rd_regions,
- struct vgic_redist_region, list);
+ rdreg = list_first_entry_or_null(&vgic->rd_regions,
+ struct vgic_redist_region, list);
if (!rdreg)
addr_ptr = &undef_value;
else
--
2.26.3

2021-06-21 15:27:29

by Greg KH

Subject: Re: [PATCH for-stable-5.4] KVM: arm/arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST read

On Mon, Jun 21, 2021 at 02:42:32PM +0200, Eric Auger wrote:
> When reading the base address of the a REDIST region
> through KVM_VGIC_V3_ADDR_TYPE_REDIST we expect the
> redistributor region list to be populated with a single
> element.
>
> However list_first_entry() expects the list to be non empty.
> Instead we should use list_first_entry_or_null which effectively
> returns NULL if the list is empty.
>
> Fixes: dbd9733ab674 ("KVM: arm/arm64: Replace the single rdist region by a list")
> Cc: <[email protected]> # v5.4
> Signed-off-by: Eric Auger <[email protected]>
> Reported-by: Gavin Shan <[email protected]>
> Signed-off-by: Marc Zyngier <[email protected]>
> Link: https://lore.kernel.org/r/[email protected]
> ---
> virt/kvm/arm/vgic/vgic-kvm-device.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

Both now queued up, thanks.

Next time, give us a hint as to what the upstream commit id is, so that
we do not have to dig it up ourselves :)

thanks,

greg k-h

2021-06-21 15:40:12

by Eric Auger

Subject: Re: [PATCH for-stable-5.4] KVM: arm/arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST read

Hi Greg,

On 6/21/21 5:23 PM, Greg KH wrote:
> On Mon, Jun 21, 2021 at 02:42:32PM +0200, Eric Auger wrote:
>> When reading the base address of the a REDIST region
>> through KVM_VGIC_V3_ADDR_TYPE_REDIST we expect the
>> redistributor region list to be populated with a single
>> element.
>>
>> However list_first_entry() expects the list to be non empty.
>> Instead we should use list_first_entry_or_null which effectively
>> returns NULL if the list is empty.
>>
>> Fixes: dbd9733ab674 ("KVM: arm/arm64: Replace the single rdist region by a list")
>> Cc: <[email protected]> # v5.4
>> Signed-off-by: Eric Auger <[email protected]>
>> Reported-by: Gavin Shan <[email protected]>
>> Signed-off-by: Marc Zyngier <[email protected]>
>> Link: https://lore.kernel.org/r/[email protected]
>> ---
>> virt/kvm/arm/vgic/vgic-kvm-device.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
> Both now queued up, thanks.
>
> Next time, give us a hint as to what the upstream commit id is, so that
> we do not have to dig it up ourselves :)
Sure I will.

Thanks!

Eric
>
> thanks,
>
> greg k-h
>