lockdep: Add CPU-idle/offline warning to lockdep-RCU splat (c5fdcec9) · Commits · 戴 / test

It is illegal to use RCU from a CPU that has reported idleness or offlinedness to RCU. However, it can be quite difficult to determine from a stack trace whether or not a given CPU is idle or offline. Therefore, this commit adds idle/offline diagnostics to the lockdep-RCU error message. Signed-off-by:

Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by:

Paul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/lockdep.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -4176,7 +4176,13 @@ void lockdep_rcu_suspicious(const char file, const int line, const char s)
		printk("-------------------------------\n");
		printk("%s:%d %s!\n", file, line, s);
		printk("\nother info that might help us debug this:\n\n");
		printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks);
		printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
		!rcu_lockdep_current_cpu_online()
		? "RCU used illegally from offline CPU!\n"
		: rcu_is_cpu_idle()
		? "RCU used illegally from idle CPU!\n"
		: "",
		rcu_scheduler_active, debug_locks);

		/*
		* If a CPU is in the RCU-free window in idle (ie: in the section

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