X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=kernel%2Ftrace%2Ftrace_stack.c;fp=kernel%2Ftrace%2Ftrace_stack.c;h=dda9e6742950305f36fbe920f9fe0c6f68d83fbf;hb=22402cd0af685c1a5d067c87db3051db7fff7709;hp=0bd212af406c49fc64ad308112e9ad7fab1eb4ff;hpb=d227c3ae4e94e5eb11dd780a811f59e1a7b74ccd;p=linux-2.6-block.git

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 0bd212af406c..dda9e6742950 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -91,9 +91,19 @@ check_stack(unsigned long ip, unsigned long *stack)
 	if (!object_is_on_stack(stack))
 		return;
 
+	/* Can't do this from NMI context (can cause deadlocks) */
+	if (in_nmi())
+		return;
+
 	local_irq_save(flags);
 	arch_spin_lock(&stack_trace_max_lock);
 
+	/*
+	 * RCU may not be watching, make it see us.
+	 * The stack trace code uses rcu_sched.
+	 */
+	rcu_irq_enter();
+
 	/* In case another CPU set the tracer_frame on us */
 	if (unlikely(!frame_size))
 		this_size -= tracer_frame;
@@ -175,6 +185,7 @@ check_stack(unsigned long ip, unsigned long *stack)
 	}
 
  out:
+	rcu_irq_exit();
 	arch_spin_unlock(&stack_trace_max_lock);
 	local_irq_restore(flags);
 }