As explained here [1], livepatch modules are failing to initialize properly because the ftrace coming module notifier (which calls ftrace_module_enable()) runs after the livepatch module notifier (which enables the patch(es)). Thus livepatch attempts to apply patches to modules before ftrace_module_enable() is even called for the corresponding module(s). Separate klp_module_notify() into coming and going notifiers and tweak the priorities to fix the order in which the ftrace and livepatch notifiers are called.
Tested the changes with a test livepatch module that patches 9p and nilfs2, and verified that the issue is fixed. Patch 1/2 based on the 'for-next' branch in livepatching - git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching.git Patch 2/2 based on the 'ftrace/core' branch in linux-trace - git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git [1] http://lkml.kernel.org/g/20160128204033.ga32...@packer-debian-8-amd64.digitalocean.com Jessica Yu (2): livepatch: Implement separate coming and going module notifiers ftrace: Adjust priority of ftrace module notifier kernel/livepatch/core.c | 128 +++++++++++++++++++++++++++--------------------- kernel/trace/ftrace.c | 7 ++- 2 files changed, 79 insertions(+), 56 deletions(-) -- 2.4.3
