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Commit c5fdcec9 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Paul E. McKenney
Browse files

lockdep: Add CPU-idle/offline warning to lockdep-RCU splat 



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: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent c0cfbbb0

kernel/lockdep.c

+7 −1
Original line number Original line 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("-------------------------------\n");

	printk("%s:%d %s!\n", file, line, s);

	printk("%s:%d %s!\n", file, line, s);

	printk("\nother info that might help us debug this:\n\n");

	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

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