Re: [PATCH 1/2] LoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust

[Aurelien Jarno]

Hi,

On 2026-03-23 15:56, Bibo Mao wrote:
> 
> 
> On 2026/3/23 下午3:08, Huacai Chen wrote:
> > On Mon, Mar 23, 2026 at 11:16 AM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
> > > 
> > > 
> > > 
> > > On 2026/3/22 下午9:53, Huacai Chen wrote:
> > > > kvm_get_vcpu_by_cpuid() takes a cpuid parameter whose type is int, so
> > > > cpuid can be negative. Let kvm_get_vcpu_by_cpuid() return NULL for this
> > > > case so as to make it more robust.
> > > > 
> > > > This fix an out-of-bounds access to kvm_arch::phyid_map::phys_map[].
> > > > 
> > > > Cc: <stable@xxxxxxxxxxxxxxx>
> > > > Fixes: 73516e9da512adc ("LoongArch: KVM: Add vcpu mapping from physical cpuid")
> > > > Reported-by: Aurelien Jarno <aurel32@xxxxxxxxxx>
> > > > Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1131431
> > > > Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> > > > ---
> > > >    arch/loongarch/kvm/vcpu.c | 3 +++
> > > >    1 file changed, 3 insertions(+)
> > > > 
> > > > diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
> > > > index 8ffd50a470e6..831f381a8fd1 100644
> > > > --- a/arch/loongarch/kvm/vcpu.c
> > > > +++ b/arch/loongarch/kvm/vcpu.c
> > > > @@ -588,6 +588,9 @@ struct kvm_vcpu *kvm_get_vcpu_by_cpuid(struct kvm *kvm, int cpuid)
> > > >    {
> > > >        struct kvm_phyid_map *map;
> > > > 
> > > > +     if (cpuid < 0)
> > > > +             return NULL;
> > > > +
> > > >        if (cpuid >= KVM_MAX_PHYID)
> > > >                return NULL;
> > > > 
> > > > 
> > > 
> > > if (cpuid < 0 || cpuid >= KVM_MAX_PHYID)?
> > > however both are OK for me.
> > I use a similar style as kvm_get_vcpu_by_id(). :)
> > 
> > But there is another warning which can't be solved by this series (and
> > I doubt whether it can be solved unless revert 01a8e68396a6d51f5b).
> > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1131431
> 
> what is the kernel config file with bug
>    https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1131431
> 

I have just sent the kernel config to the bug report.

Regards
Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@xxxxxxxxxxx                     http://aurel32.net