Comment 0 for bug 1771844

== Comment: #0 - Kamalesh Babulal - 2018-05-15 09:37:52 ==
Livepatch has a consistency model which is a hybrid of kGraft and kpatch: it uses kGraft's per-task consistency and syscall barrier switching combined with kpatch's stack trace switching. The current approach is stack checking of sleeping tasks. If no affected functions are on the stack of a given task, the task is patched. In most cases this will patch most or all of the tasks on the first try. Otherwise, it'll keep trying periodically. This patch implements the reliable stack tracing for consistency model a.k.a HAVE_RELIABLE_STACKTRACE.

This will help in switching livepatching implementation to basic per-task consistency model. It is the foundation, which will help us enable security patches changing function or data semantics. This is the biggest remaining piece needed on ppc64le to make livepatch more generally useful.

https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id=df78d3f6148092d33a9a24c7a9cfac