linux-kernel - Re: [PATCH arm 1/1] arm: Use _rcuidle tracepoint to allow use from idle

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Message-ID: <20160426151725.657ae70c@gandalf.local.home>
Date:	Tue, 26 Apr 2016 15:17:25 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Tony Lindgren <tony@...mide.com>
Cc:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	linux-kernel@...r.kernel.org, mingo@...nel.org,
	Russell King <linux@....linux.org.uk>,
	linux-omap@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH arm 1/1] arm: Use _rcuidle tracepoint to allow use from
 idle

On Tue, 26 Apr 2016 11:29:39 -0700
Tony Lindgren <tony@...mide.com> wrote:

> * Paul E. McKenney <paulmck@...ux.vnet.ibm.com> [160426 10:53]:
> > Does the following patch help?  
> 
> It just changes the output.. See below.
> 
> > It is quite possible that there are quite a few more of these.  If this
> > is the case, then one way to make the kernel list more of them on a
> > given boot is to build with CONFIG_PROVE_RCU_REPEATEDLY=y.  
> 
> OK
> 
> Regards,
> 
> Tony
> 
> 8< ------------------
> CPU: Testing write buffer coherency: ok
> CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
> 
> 
> RCU used illegally from idle CPU!
> rcu_scheduler_active = 1, debug_locks = 0
> RCU used illegally from extended quiescent state!
> no locks held by swapper/1/0.
> 
> stack backtrace:
> CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.6.0-rc5-next-20160426+ #1113
> Hardware name: Generic OMAP4 (Flattened Device Tree)
> [<c0110290>] (unwind_backtrace) from [<c010c3a8>] (show_stack+0x10/0x14)
> [<c010c3a8>] (show_stack) from [<c047ff88>] (dump_stack+0xb0/0xe4)
> [<c047ff88>] (dump_stack) from [<c012c014>] (pwrdm_set_next_pwrst+0x100/0x1d4)
> [<c012c014>] (pwrdm_set_next_pwrst) from [<c0126120>] (omap4_enter_lowpower+0xc8/0x230)
> [<c0126120>] (omap4_enter_lowpower) from [<c0126c24>] (omap_enter_idle_coupled+0x6c/0x254)
> [<c0126c24>] (omap_enter_idle_coupled) from [<c0601dfc>] (cpuidle_enter_state+0x80/0x3d4)
> [<c0601dfc>] (cpuidle_enter_state) from [<c0603d30>] (cpuidle_enter_state_coupled+0x348/0x390)
> [<c0603d30>] (cpuidle_enter_state_coupled) from [<c0183d34>] (cpu_startup_entry+0x198/0x3a0)
> [<c0183d34>] (cpu_startup_entry) from [<8010162c>] (0x8010162c)
> hw-breakpoint: Failed to enable monitor mode on CPU 0.

Time to play "Whack-a-Mole"(TM)

Signed-off-by: Steven Rostedt <rostedt@...dmis.org>
---
diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index 78af6d8cf2e2..12b66b5bcc55 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -523,8 +523,8 @@ int pwrdm_set_next_pwrst(struct powerdomain *pwrdm, u8 pwrst)
 
 	if (arch_pwrdm && arch_pwrdm->pwrdm_set_next_pwrst) {
 		/* Trace the pwrdm desired target state */
-		trace_power_domain_target(pwrdm->name, pwrst,
-					  smp_processor_id());
+		trace_power_domain_target_rcuidle(pwrdm->name, pwrst,
+						  smp_processor_id());
 		/* Program the pwrdm desired target state */
 		ret = arch_pwrdm->pwrdm_set_next_pwrst(pwrdm, pwrst);
 	}