What is DEBUG_SLAB and REDZONE?
 

Hi,
I am facing a wierd sutation where a PPC blade running RHEL reboots with meaningless calltraces, The pmem logs are also not meaningful, the issue seemed to be of memory corruption, someone suggested to enable DEBUG_SLAB and redzoning, am wondering what they are and how can enabling them be useful.

Please let me know about this.
Regards,
//P Ravi Rao

The redzone is for loading and unloading only. Enabling redzone reserves a certain amount of space on the stack for use by hardware when handling interrupts, x86_64 machines need to have this on and it should be enabled by default already on those architectures, if you are making your own module for this type of platform then you need to make sure its on in your compile flags or pull in the kernels compile flags since they should have it. PPC architecture might have this same requirement, I don't know.

slab debugging puts poison markers in memory so you can catch double frees and check to see if you are using unallocated space, it might do some other things but thats what I recall offhand.