rcu: Put panic_on_rcu_stall() after expedited RCU CPU stall warnings

When a normal RCU CPU stall warning is encountered with the
panic_on_rcu_stall sysfs variable is set, the system panics only after
the stall warning is printed.  But when an expedited RCU CPU stall
warning is encountered with the panic_on_rcu_stall sysfs variable is
set, the system panics first, thus never printing the stall warning.
This commit therefore brings the expedited stall warning into line with
the normal stall warning by printing first and panicking afterwards.

Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 571b0a700ccedba5500b0f66b07b50a811954688..f05a15b11fa0ce189e7a8fc6f77fc87b975b0ffc 100644 (file)
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -623,7 +623,6 @@ static void synchronize_rcu_expedited_wait(void)
                        return;
                if (rcu_stall_is_suppressed())
                        continue;
-               panic_on_rcu_stall();
                trace_rcu_stall_warning(rcu_state.name, TPS("ExpeditedStall"));
                pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {",
                       rcu_state.name);
@@ -671,6 +670,7 @@ static void synchronize_rcu_expedited_wait(void)
                        }
                }
                jiffies_stall = 3 * rcu_exp_jiffies_till_stall_check() + 3;
+               panic_on_rcu_stall();
        }
 }