Commit-ID: c5fdcec927ee31fc96e92339c3a83ac6e0725289
Gitweb: http://git.kernel.org/tip/c5fdcec927ee31fc96e92339c3a83ac6e0725289
Author: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
AuthorDate: Mon, 30 Jan 2012 08:46:32 -0800
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Tue, 21 Feb 2012 09:06:06 -0800
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: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/lockdep.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 8889f7d..ea9ee45 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -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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