Re: linux-next: manual merge of the kvm tree with Linus' tree

From: Stephen Rothwell
Date: Thu Feb 01 2018 - 19:20:48 EST


Hi Radim,

On Thu, 1 Feb 2018 16:22:44 +0100 Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx> wrote:
>
> I wasn't sure if the pti top branch is final, so I pulled hyper-v topic
> branch that also also contains v4.15. This and the SEV feature
> conflicts should be gone now,

That merge would have been a good place to add the following merge
resolution fix patch I have been carrying:

From: Eric Biggers <ebiggers@xxxxxxxxxx>
Subject: KVM: x86: don't forget vcpu_put() in kvm_arch_vcpu_ioctl_set_sregs()
Date: Thu, 21 Dec 2017 01:30:30 +0100

Due to a bad merge resolution between commit f29810335965 ("KVM/x86:
Check input paging mode when cs.l is set") and commit b4ef9d4e8cb8
("KVM: Move vcpu_load to arch-specific kvm_arch_vcpu_ioctl_set_sregs"),
there is a case in kvm_arch_vcpu_ioctl_set_sregs() where vcpu_put() is
not called after vcpu_get(). Fix it.

Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ea3a98196753..f4e8b5089b28 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7624,7 +7624,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
goto out;

if (kvm_valid_sregs(vcpu, sregs))
- return -EINVAL;
+ goto out;

apic_base_msr.data = sregs->apic_base;
apic_base_msr.host_initiated = true;

--
Cheers,
Stephen Rothwell