Commit 64ec8b6a authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Uladzislau Rezki (Sony)
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ftrace: Choose RCU Tasks based on TASKS_RCU rather than PREEMPTION 



The advent of CONFIG_PREEMPT_AUTO, AKA lazy preemption, will mean that
even kernels built with CONFIG_PREEMPT_NONE or CONFIG_PREEMPT_VOLUNTARY
might see the occasional preemption, and that this preemption just might
happen within a trampoline.

Therefore, update ftrace_shutdown() to invoke synchronize_rcu_tasks()
based on CONFIG_TASKS_RCU instead of CONFIG_PREEMPTION.

[ paulmck: Apply Steven Rostedt feedback. ]

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ankur Arora <ankur.a.arora@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <linux-trace-kernel@vger.kernel.org>
Signed-off-by: default avatarUladzislau Rezki (Sony) <urezki@gmail.com>
parent 1e52af7f

kernel/trace/ftrace.c

+1 −2
Original line number Diff line number Diff line
@@ -3157,7 +3157,6 @@ int ftrace_shutdown(struct ftrace_ops *ops, int command) 
		 * synchronize_rcu_tasks() will wait for those tasks to

		 * execute and either schedule voluntarily or enter user space.

		 */

		if (IS_ENABLED(CONFIG_PREEMPTION))

		synchronize_rcu_tasks();



		ftrace_trampoline_free(ops);