On Thu, May 04, 2017 at 12:55:13PM +0200, Petr Mladek wrote: > Steven and Paul recently discussed some issues when using RCU > functionality in ftrace handlers. A good summary can be found at > https://lkml.kernel.org/r/20170412115304.3077dbc8@xxxxxxxxxxxxxxxxxx > > This discussion made us to revisit the ftrace handler used by > the livepatches. Some changes seem to be needed. A perfect solution > looks rather complicated. I have implemented a sub-optimal > one and split it into three patches for easier review. > > Please, note that we were on the safe side before introducing > the hybrid consistency model. The ftrace handler worked correctly > with empty function stack. Also the patch removal was not possible. > But we need to be more careful now. I don't know enough to say much about the live patching, but the characterization of how RCU works is correct. Thanx, Paul > Petr Mladek (3): > livepatch/rcu: Guarantee consistency when patching idle kthreads > livepatch/rcu: Warn when system consistency is broken in RCU code > livepatch/rcu: Disable livepatch removal when safety is not guaranteed > > Documentation/livepatch/livepatch.txt | 19 +++++++++++++++++++ > kernel/livepatch/patch.c | 14 ++++++++++++++ > kernel/livepatch/transition.c | 7 ++++++- > kernel/livepatch/transition.h | 2 ++ > 4 files changed, 41 insertions(+), 1 deletion(-) > > -- > 1.8.5.6 > -- 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
