linux-kernel - [PATCH 6/6] cpuidle: Fix poll

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Date:   Mon, 23 Jan 2023 21:50:15 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     mingo@...nel.org
Cc:     will@...nel.org, peterz@...radead.org, boqun.feng@...il.com,
        mark.rutland@....com, tglx@...utronix.de, bp@...en8.de,
        dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
        seanjc@...gle.com, pbonzini@...hat.com, jgross@...e.com,
        srivatsa@...il.mit.edu, amakhalov@...are.com,
        pv-drivers@...are.com, rostedt@...dmis.org, mhiramat@...nel.org,
        wanpengli@...cent.com, vkuznets@...hat.com,
        boris.ostrovsky@...cle.com, rafael@...nel.org,
        daniel.lezcano@...aro.org, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, dietmar.eggemann@....com,
        bsegall@...gle.com, mgorman@...e.de, bristot@...hat.com,
        vschneid@...hat.com, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, virtualization@...ts.linux-foundation.org,
        linux-trace-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        kernel test robot <oliver.sang@...el.com>
Subject: [PATCH 6/6] cpuidle: Fix poll_idle() noinstr annotation

The instrumentation_begin()/end() annotations in poll_idle() were
complete nonsense. Specifically they caused tracing to happen in the
middle of noinstr code, resulting in RCU splats.

Now that local_clock() is noinstr, mark up the rest and let it rip.

Fixes: 00717eb8c955 ("cpuidle: Annotate poll_idle()")
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reported-by: kernel test robot <oliver.sang@...el.com>
Link: https://lore.kernel.org/oe-lkp/202301192148.58ece903-oliver.sang@intel.com
---
 drivers/cpuidle/cpuidle.c    |    2 +-
 drivers/cpuidle/poll_state.c |    2 --
 2 files changed, 1 insertion(+), 3 deletions(-)

--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -426,7 +426,7 @@ void cpuidle_reflect(struct cpuidle_devi
  * @dev:   the cpuidle device
  *
  */
-u64 cpuidle_poll_time(struct cpuidle_driver *drv,
+__cpuidle u64 cpuidle_poll_time(struct cpuidle_driver *drv,
 		      struct cpuidle_device *dev)
 {
 	int i;
--- a/drivers/cpuidle/poll_state.c
+++ b/drivers/cpuidle/poll_state.c
@@ -15,7 +15,6 @@ static int __cpuidle poll_idle(struct cp
 {
 	u64 time_start;
 
-	instrumentation_begin();
 	time_start = local_clock();
 
 	dev->poll_time_limit = false;
@@ -42,7 +41,6 @@ static int __cpuidle poll_idle(struct cp
 	raw_local_irq_disable();
 
 	current_clr_polling();
-	instrumentation_end();
 
 	return index;
 }