On Thu 08-02-18 13:35:08, David Rientjes 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: > > vmalloc: allocation failure: 0 bytes, mode:0x24000c2(GFP_KERNEL|__GFP_HIGHMEM) I am not arguing about the kvm change but do we actaully want to warn for 0 sized allocations? This just doesn't make much sense to me. In other words don't we want this? diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 673942094328..c5d832510c54 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1748,7 +1748,9 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, unsigned long real_size = size; size = PAGE_ALIGN(size); - if (!size || (size >> PAGE_SHIFT) > totalram_pages) + if (!size) + return NULL; + if ((size >> PAGE_SHIFT) > totalram_pages) goto fail; area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED | -- Michal Hocko SUSE Labs
