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. Paolo
