3820b513a2
Provide CONFIG_PROVE_RCU sanity checks to ensure we are always reading the offloaded state of an rdp in a safe and stable way and prevent from its value to be changed under us. We must either hold the barrier mutex, the cpu-hotplug lock (read or write) or the nocb lock. Local non-preemptible reads are also safe. NOCB kthreads and timers have their own means of synchronization against the offloaded state updaters. Cc: Josh Triplett <josh@joshtriplett.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Neeraj Upadhyay <neeraju@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>