initramfs init has generated signal 11 but has no handler for it

Question

I built an embedded Linux kernel 2.6.19 on powerpc MPC860 CPU. I created a initramfs.cpio with only one "init" file in the / directory(no other files and no other directories). The init is cross-compiled to an elf format file. The init only set int i=0 and return 0. All I want to do is to make sure the kernel can successfully call this init. Then I will add more stuff in the file system later. But the serial port output error message "init has generated signal 11 but has no handler for it". I have BDM interface connected to the board. The serial port is OK. gdb is OK. I cannot set breakpoint to the kernel_execve() because I use u-boot "bootm " command to boot the kernel. Is there any method to debug it?