Is a NULL check on 'drv1->format_name' missing here? https://github.com/qemu/qemu/blob/cc818a2148c5f321bdeb8e5564bdb2914e824600/block.c#L400-L403
if (!strcmp(drv1->format_name, format_name)) {
While it is checked in similar case:
https://github.com/qemu/qemu/blob/cc818a2148c5f321bdeb8e5564bdb2914e824600/block.c#L797-L800
if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) {
