kzalloc() is a memory allocation function which can return NULL when
some internal memory errors happen. So it is better to check the
return value of it to prevent potential wrong memory access or
memory leak.
Signed-off-by: NXiaoke Wang <xkernel.wang@foxmail.com>
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>