Re: [PATCH 16/36] rcu: Fix rcu_idle_exit()
From: Mark Rutland <mark.rutland@arm.com>
Date: 2022-06-14 16:15:53
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On Wed, Jun 08, 2022 at 04:27:39PM +0200, Peter Zijlstra wrote:
Current rcu_idle_exit() is terminally broken because it uses
local_irq_{save,restore}(), which are traced which uses RCU.
However, now that all the callers are sure to have IRQs disabled, we
can remove these calls.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>Acked-by: Mark Rutland <mark.rutland@arm.com> Mark.
quoted hunk ↗ jump to hunk
--- kernel/rcu/tree.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)--- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c@@ -659,7 +659,7 @@ static noinstr void rcu_eqs_enter(bool u * If you add or remove a call to rcu_idle_enter(), be sure to test with * CONFIG_RCU_EQS_DEBUG=y. */ -void rcu_idle_enter(void) +void noinstr rcu_idle_enter(void) { lockdep_assert_irqs_disabled(); rcu_eqs_enter(false);@@ -896,13 +896,10 @@ static void noinstr rcu_eqs_exit(bool us * If you add or remove a call to rcu_idle_exit(), be sure to test with * CONFIG_RCU_EQS_DEBUG=y. */ -void rcu_idle_exit(void) +void noinstr rcu_idle_exit(void) { - unsigned long flags; - - local_irq_save(flags); + lockdep_assert_irqs_disabled(); rcu_eqs_exit(false); - local_irq_restore(flags); } EXPORT_SYMBOL_GPL(rcu_idle_exit);
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