On 02/14/2018 11:10 AM, Paolo Bonzini wrote: > On 14/02/2018 02:03, David Rientjes wrote: >> On Tue, 13 Feb 2018, Paolo Bonzini wrote: >> >>>>> The KVM_SET_GSI_ROUTING ioctl does a vmalloc() of >>>>> sizeof(struct kvm_irq_routing_entry) multiplied by a user-supplied value. >>>>> This can be up to 4096 entries on architectures such as arm64 and s390 >>>>> (and the upper bound may be increased on s390 eventually). >>>>> >>>>> This can produce a vmalloc allocation failure warning: >>>>> >>>> [...] >>>>> kvm_vm_ioctl+0x910/0x15e0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:4153 >>>> >>>> ^^^^^ >>>> >>>>> @@ -3063,7 +3063,8 @@ static long kvm_vm_ioctl(struct file *filp, >>>> >>>> ^^^^^ >>>> >>>> >>>> Are you sure that you got the right vmalloc? >>> >>> Nice catch! But well, it's the only one in the whole file. :) >>> >>> That seems very much like an old patch then. I'm unqueuing it. >>> >> >> It's not a catch at all, the fact that I saw this warning with an older >> kernel for KVM_SET_GSI_ROUTING doesn't mean that I can't patch it with an >> upstream kernel. Would you prefer I remove the stack trace completely? > > The upstream kernel doesn't warn. It checks "if (routing.nr)" before > calling vmalloc. It will warn of the vmalloc space is really exhausted. But then I really ask myself if we really want to suppress this warning. This should be a big ALERT to the host admin.
