Before reading data in dfi_vmcoreinfo_init(), check the validity
of the memory range. Otherwise this can result in a segmentation fault when
zgetdump is given a very small dump, e.g. S390 DASD single-volume dump of
size 0x10 bytes.
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>