kGraft — live kernel patching from SUSE
SUSE has announced
the existence of kGraft,
a mechanism for applying kernel patches without the need to reboot the
system. It is similar to ksplice in functionality, but the implementation
appears to be rather different and the developers plan to try to get it
merged into the mainline kernel. "kGraft builds on technologies and
ideas that are already present in the kernel: ftrace and its mcount-based
reserved space in function headers, the INT3/IPI-NMI patching also used in
jumplabels, and RCU-like update of code that does not require stopping the
kernel. A kGraft patch is a kernel module and fully relies on the
in-kernel module loader to link the new code with the kernel. Thanks to
all that, the design can be nicely minimalistic." The first code
release is planned for March.