On Fri, Feb 05, 2016 at 10:08:15PM -0500, Jessica Yu wrote: > 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). As a result, patch modules break. Ftrace code must run before > livepatch on module load, and the reverse is true on module unload. > > For ftrace and livepatch, order of initialization (plus exit/cleanup code) is > important for loading and unloading modules, and using module notifiers to > perform this work is not ideal since it is not always clear what gets called > when. In this patchset, dependence on the module notifier call chain is removed > in favor of hard coding the corresponding function calls in the module loader. > This promotes better code visibility and ensures that ftrace and livepatch code > get called in the correct order on patch module load and unload. > > Tested the changes with a test livepatch module that patches 9p and nilfs2, > and verified that the issue described in [1] is fixed. Since Rusty agreed to your suggested changes for splitting up complete_formation() and for setting mod->state = MODULE_STATE_GOING before calling the going notifiers in the error path, can you do a v4 with those changes? They should probably be split up like: 1. split up complete_formation() 2. set MODULE_STATE_GOING before calling going notifiers in error path 3. remove ftrace module notifier 4. remove livepatch module notifier -- Josh -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
