3  * RCU CPU stall warnings for normal RCU grace periods
19 /* panic() on RCU Stall sysctl. */
79 /* Don't do RCU CPU stall warnings during long sysrq printouts. */
92 /* Don't print RCU CPU stall warnings during a kernel panic. */
119 		panic("RCU Stall\n");  in panic_on_rcu_stall()
140 // Interaction with RCU grace periods
157 /* Zero ->ticks_this_gp and snapshot the number of RCU softirq handlers. */
187  * Handler for the irq_work request posted about halfway into the RCU CPU
208 // Printing RCU CPU stall warnings
213  * Dump detailed information for all tasks blocking the current RCU
239 // Communicate task state back to the RCU CPU stall warning request.
248  * current RCU grace period.
263  * Scan the current list of tasks blocked within RCU read-side critical
313  * Because preemptible RCU does not exist, we never have to check for
314  * tasks blocked within RCU read-side critical sections.
321  * Because preemptible RCU does not exist, we never have to check for
322  * tasks blocked within RCU read-side critical sections.
389 /* Is the RCU grace-period kthread being starved of CPU time? */
452  * If the specified CPU is aware of the current RCU grace period, then
455  * of RCU grace periods that this CPU is ignorant of, for example, "1"
530 			pr_err("RCU grace-period kthread stack dump:\n");  in rcu_check_gp_kthread_starvation()
533 				pr_err("RCU GP kthread last ran on offline CPU %d.\n", cpu);  in rcu_check_gp_kthread_starvation()
535 				pr_err("Stack dump where RCU GP kthread last ran:\n");  in rcu_check_gp_kthread_starvation()
594 	 * See Documentation/RCU/stallwarn.rst for info on how to debug  in print_other_cpu_stall()
595 	 * RCU CPU stall warnings.  in print_other_cpu_stall()
670 	 * See Documentation/RCU/stallwarn.rst for info on how to debug  in print_cpu_stall()
671 	 * RCU CPU stall warnings.  in print_cpu_stall()
702 	 * Attempt to revive the RCU machinery by forcing a context switch.  in print_cpu_stall()
704 	 * A context switch would normally allow the RCU state machine to make  in print_cpu_stall()
781 		 * the watchdog like an RCU stall. Check to see if the host  in check_cpu_stall()
810 // RCU forward-progress mechanisms, including for callback invocation.
814  * Check to see if a failure to end RCU priority inversion was due to
816  * is nothing that RCU priority boosting can do to help, so we shouldn't
817  * count this as an RCU priority boosting failure.  A return of true says
818  * RCU priority boosting is to blame, and false says otherwise.  If false
865 	// Can't blame CPUs, so must blame RCU priority boosting.  in rcu_check_boost_fail()
933 	pr_info("RCU callbacks invoked since boot: %lu\n", cbs);  in show_rcu_gp_kthreads()
940  * RCU to come out of its idle mode.
1038 /* Commandeer a sysrq key to dump RCU's tree. */
1050 	.help_msg = "show-rcu(y)",
1051 	.action_msg = "Show RCU tree",
1067 // RCU CPU stall-warning notifiers
1072  * rcu_stall_chain_notifier_register - Add an RCU CPU stall notifier
1075  * Adds an RCU CPU stall notifier to an atomic notifier chain.
1086 	WARN(1, "Adding %pS() to RCU stall notifier list (%s).\n", n->notifier_call,  in rcu_stall_chain_notifier_register()
1087 	     rcsn ? "possibly suppressing RCU CPU stall warnings" : "failed, so all is well");  in rcu_stall_chain_notifier_register()
1095  * rcu_stall_chain_notifier_unregister - Remove an RCU CPU stall notifier
1098  * Removes an RCU CPU stall notifier from an atomic notifier chain.
1109  * rcu_stall_notifier_call_chain - Call functions in an RCU CPU stall notifier chain
1113  * Calls each function in the RCU CPU stall notifier chain in turn, which
1117  * This is for use within RCU, hence the omission of the extra asterisk