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authorThomas Gleixner <tglx@linutronix.de>2020-05-21 22:05:16 +0200
committerIngo Molnar <mingo@kernel.org>2020-05-26 19:05:11 +0200
commit07325d4a90d2d84de45cc07b134fd0f023dbb971 (patch)
tree0c0437193ef9e2501abb778d25a7f5a3d3429935 /kernel/rcu
parentaaf2bc50df1f4bfc6857fc601fc7b21d5a18c6a1 (diff)
downloadlinux-07325d4a90d2d84de45cc07b134fd0f023dbb971.tar.bz2
rcu: Provide rcu_irq_exit_check_preempt()
Provide a debug check which can be invoked from exception return to kernel mode before an attempt is made to schedule. Warn if RCU is not ready for this. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/r/20200521202117.089709607@linutronix.de
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b7f8c494d1d1..d8e9dbbefcfa 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -765,6 +765,24 @@ void rcu_irq_exit_preempt(void)
"RCU in extended quiescent state!");
}
+#ifdef CONFIG_PROVE_RCU
+/**
+ * rcu_irq_exit_check_preempt - Validate that scheduling is possible
+ */
+void rcu_irq_exit_check_preempt(void)
+{
+ lockdep_assert_irqs_disabled();
+
+ RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nesting) <= 0,
+ "RCU dynticks_nesting counter underflow/zero!");
+ RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nmi_nesting) !=
+ DYNTICK_IRQ_NONIDLE,
+ "Bad RCU dynticks_nmi_nesting counter\n");
+ RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(),
+ "RCU in extended quiescent state!");
+}
+#endif /* #ifdef CONFIG_PROVE_RCU */
+
/*
* Wrapper for rcu_irq_exit() where interrupts are enabled.
*