trunk96 / schedule_hook

Linux Kernel schedule() function patcher

schedule-hook

A kernel module that dynamically patches the Linux kernel scheduler so as to allow running a custom function upon thread reschedule This is the schedule-hook kernel module, to allow running a custom function e.g. in another module, upon thread reschedule

This module can be used either in cross compilation with the one containing the custom function or not

This module patches at run-time the kernel schedule() and enables running a schedule-hook function as the last task of thread re-schedule

The schedule-hook function is embedded within this module, it checks the value of a function pointer and in case it is not null the target functio is called

In cross compilation the function pointer is exported as a symbol to be updated while mounting the module containing the custom functions to be run

Otherwise, the function ponter is accessible as a pseudofile called /sys/module/schedule_hook/parameters/the_hook

In the latter configuration, after mounting the module, you can load any function pointer you would like (pointing to kernel stuff) by writing it on that pseudofile

The custom function to be run needs to get no paramter in input

Please check with the following configuration macros to manage the configuration of this module:

• DEBUG and DEBUG_SCHEDULE_HOOK for enabling or disabling debugging/audit stuff
• SYS_FS for enabling of disabling the reliance on /sys

NOTE: the custom function is expected to be non-blocking, in case it is blocking the unmount of this module may hang

NOTE: this module should be unmounted before unmounting the one containing the custom function otherwise your kernel will likely crash

The code has been developed by:

• Francesco Quaglia [email protected]
• Alessandro Pellegrini [email protected]
• Emanuele De Santis [email protected]

and is Copyright (C) 2017 HPDCS Group, http://www.dis.uniroma1.it/~hpdcs

For installation and usage information, please refer to INSTALL.