From cc5b83a9f884fe8722a275069a5a6fde39988455 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 3 Mar 2010 07:46:59 -0800 Subject: [PATCH] rcu: Add control variables to lockdep_rcu_dereference() diagnostics Add the values of rcu_scheduler_active() and debug_locks() to the lockdep_rcu_dereference() output to help diagnose RCU lockdep splats that occur shortly after the scheduler starts. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1267631219-8713-4-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 0c30d0455de1..681bc2e1e187 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3822,6 +3822,7 @@ void lockdep_rcu_dereference(const char *file, const int line) printk("%s:%d invoked rcu_dereference_check() without protection!\n", file, line); 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); lockdep_print_held_locks(curr); printk("\nstack backtrace:\n"); dump_stack();