打印“ VFS：已挂载的根（ubifs文件系统）”后，Linux Kernel 3.4.1挂起。

Question

I am trying to bring up Linux-3.4.1 on our cutom MIPS based hardware. It hung after printing the line

VFS:Mounted root (ubifs filesystem)

On further debugging, it was found that kernel is hanging in free_init_mem() [arch/mips/mm/init.c] . My debug prints to determine the place of hang in free_init_mem is as below :

Freeing unused kernel memory:  8038e000 - 803bb000
Freeing unused kernel memory: 8038e000 page
Freeing unused kernel memory: 8038f000 page
Freeing unused kernel memory: 80390000 page
Freeing unused kernel memory: 80391000 page
Freeing unused kernel memory: 80392000 page
Freeing unused kernel memory: 80393000 page
Freeing unused kernel memory: 80394000 page
.....
Freeing unused kernel memory: 803b4000 page
<hang>

Any help to debug the above hang will be very useful.

Answer 1

Just some random guessing: since it hangs after freeing the init memory, I would suspect that some code is incorrectly marked __init , or some data is incorrectly marked __initdata . So the corresponding pages are freed, and the kernel crashes when it needs this data.

I guess you've done some custom kernel code to support your MIPS hardware. Double check your code to ensure that you haven't made some mistakes on this.