Debugging kernel-level slab issues when using the SLUB implementation (the default) is very powerful as the kernel has full debugging information available. It's just that it's turned off by default. There are various ways (viewports) via which we can turn on and look at slab debug-level information; a wealth of details is available! Some of the ways to do so include the following:
- Passing the slub_debug= string on the kernel command line (via the bootloader of course). This turns on full SLUB kernel-level debugging.
- The specific debug information to be seen can be fine-tuned via options passed to the slub_debug= string (passing nothing after the = implies that all SLUB debug options are enabled); for example, passing slub_debug=FZ turns on the following options:
- F: Sanity checks on (enables SLAB_DEBUG_CONSISTENCY_CHECKS); note that turning this on can slow down the system.
- Z: Red...