From: Lan Tianyu <tianyu.lan@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Eric Biggers <ebiggers3@gmail.com>,
kvm@vger.kernel.org
Cc: rkrcmar@redhat.com, christoffer.dall@linaro.org, x86@kernel.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
Eric Biggers <ebiggers@google.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Linux-Next Mailing List <linux-next@vger.kernel.org>
Subject: Re: [PATCH linux-next] KVM: x86: don't forget vcpu_put() in kvm_arch_vcpu_ioctl_set_sregs()
Date: Thu, 21 Dec 2017 10:45:54 +0800 [thread overview]
Message-ID: <1bed30da-d01f-ecfd-8024-d7c402c30f15@intel.com> (raw)
In-Reply-To: <5e98adf7-809f-3b98-e8fc-6ba89e2777cf@redhat.com>
On 2017年12月21日 08:30, Paolo Bonzini wrote:
> On 21/12/2017 01:24, Eric Biggers wrote:
>> From: Eric Biggers <ebiggers@google.com>
>>
>> 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@googlegroups.com>
>> Signed-off-by: Eric Biggers <ebiggers@google.com>
>> ---
>> 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;
>>
>
> Thanks very much Eric, that was fast! Adding Stephen and the linux-next
> mailing list to Cc. Adding the kvm/master tree has already paid off.
>
> Paolo
>
Hi Paolo:
Should we check input sregs before loading vcpu? If input sregs is
invalid, the operation is redundant.
--
Best regards
Tianyu Lan
next prev parent reply other threads:[~2017-12-21 2:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-20 16:03 KASAN: use-after-free Read in __schedule syzbot
2017-12-21 0:24 ` [PATCH linux-next] KVM: x86: don't forget vcpu_put() in kvm_arch_vcpu_ioctl_set_sregs() Eric Biggers
2017-12-21 0:30 ` Paolo Bonzini
2017-12-21 1:02 ` Stephen Rothwell
2017-12-21 2:45 ` Lan Tianyu [this message]
2017-12-21 9:07 ` Paolo Bonzini
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