From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: [PATCH 16/36] rcu: Fix rcu_idle_exit() Date: Wed, 08 Jun 2022 16:27:39 +0200 Message-ID: <20220608144516.935970247@infradead.org> References: <20220608142723.103523089@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=Ae56F2/vHSxAMY+0KpLDtlvNNteu31Pblave+ocppBw=; b=K8Ynm/svRXkkOXUoDfBvEs9ZFK qWXYZy+/5CqUIjZ31FPJ7xPNOIntKDH8NSfrS8D9IkyLAoFrHvJMHJIL/IcnOIM7nqISgd0gcoDeE M8QwoOkYRBsSJ6LT9EQT7VUIsk+Z6r7wIXAFTOjV+qSGSdym/gNXacQGPlu5y6oCjnxUFjzOxnG6i Qnh3s+Cj3bWdVkKJ0fKWJQJeEH2PS1tbGo8HnFfis2/BavxNxwTBZTq7iTayiBsKwAc/kQ4fijj9Z RSxzjU7orl0A9t/vtgrMCy+RX4IT1VlY5omzQIH8HgAO6TFwqNP7RiyW7pf7sKmhryRMbaaQJQ5W8 0pAFiEvA==; List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" To: peterz@infradead.org Cc: juri.lelli@redhat.com, rafael@kernel.org, benh@kernel.crashing.org, linus.walleij@linaro.org, bsegall@google.com, guoren@kernel.org, pavel@ucw.cz, agordeev@linux.ibm.com, linux-arch@vger.kernel.org, vincent.guittot@linaro.org, mpe@ellerman.id.au, chenhuacai@kernel.org, linux-acpi@vger.kernel.org, agross@kernel.org, geert@linux-m68k.org, linux-imx@nxp.com, catalin.marinas@arm.com, xen-devel@lists.xenproject.org, mattst88@gmail.com, mturquette@baylibre.com, sammy@sammy.net, pmladek@suse.com, linux-pm@vger.kernel.org, jiangshanlai@gmail.com, Sascha Hauer , linux-um@lists.infradead.org, acme@kernel.org, tglx@linutronix.de, linux-omap@vger.kernel.org, dietmar.eggemann@arm.com, rth@twiddle.net, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, senozhatsky@chromium.org, svens@linux.ibm.com, jolsa@kernel.org, paul 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) Acked-by: Paul E. McKenney --- 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);