On Mon, 14 Mar 2016 17:18:52 +0000 Luis Henriques <luis.henriques@xxxxxxxxxxxxx> wrote: > On Fri, Mar 11, 2016 at 11:04:00PM -0800, Greg Kroah-Hartman wrote: > > > > This is a note to let you know that I've just added the patch titled > > > > tracing: Fix check for cpu online when event is disabled > > > > to the 3.10-stable tree which can be found at: > > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > > > The filename of the patch is: > > tracing-fix-check-for-cpu-online-when-event-is-disabled.patch > > and it can be found in the queue-3.10 subdirectory. > > > > If you, or anyone else, feels it should not be added to the stable tree, > > please let <stable@xxxxxxxxxxxxxxx> know about it. > > > > Please note that this patch was tagged for stable 3.18+. > Correct. That's because: > > > > Commit f37755490fe9b ("tracepoints: Do not trace when cpu is offline") added > > a check to make sure that tracepoints only get called when the cpu is > > online, as it uses rcu_read_lock_sched() for protection. This was added much earlier and fixes a real bug in various places. > > > > Commit 3a630178fd5f3 ("tracing: generate RCU warnings even when tracepoints > > are disabled") added lockdep checks (including rcu checks) for events that > > are not enabled to catch possible RCU issues that would only be triggered if > > a trace event was enabled. Commit f37755490fe9b only stopped the warnings > > when the trace event was enabled but did not prevent warnings if the trace > > event was called when disabled. The above wasn't added till 3.18, which warns when the trace event is not enabled. With the backported patch, it now triggers false warnings. But the false warnings wont exist before 3.18. It doesn't hurt to backport this patch further, it's just not necessary, unless 3a630178fd5f3 was backported too. Was it? -- Steve -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html