From mboxrd@z Thu Jan 1 00:00:00 1970 From: paulmck@linux.vnet.ibm.com (Paul E. McKenney) Date: Tue, 26 Apr 2016 14:04:07 -0700 Subject: [PATCH arm 1/1] arm: Use _rcuidle tracepoint to allow use from idle In-Reply-To: <20160426204613.GT5995@atomide.com> References: <20160426182939.GO5995@atomide.com> <20160426190755.GK3715@linux.vnet.ibm.com> <20160426193949.GP5995@atomide.com> <20160426154414.7bb33de4@gandalf.local.home> <20160426195158.GR5995@atomide.com> <20160426200613.GO3715@linux.vnet.ibm.com> <20160426201134.GA29779@linux.vnet.ibm.com> <20160426202538.GS5995@atomide.com> <20160426204148.GR3715@linux.vnet.ibm.com> <20160426204613.GT5995@atomide.com> Message-ID: <20160426210407.GT3715@linux.vnet.ibm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Apr 26, 2016 at 01:46:15PM -0700, Tony Lindgren wrote: > * Paul E. McKenney [160426 13:42]: > > On Tue, Apr 26, 2016 at 01:25:39PM -0700, Tony Lindgren wrote: > > > * Paul E. McKenney [160426 13:12]: > > > > On Tue, Apr 26, 2016 at 01:06:13PM -0700, Paul E. McKenney wrote: > > > > > On Tue, Apr 26, 2016 at 12:51:59PM -0700, Tony Lindgren wrote: > > > > > > * Steven Rostedt [160426 12:45]: > > > > > > > *Whack* *Whack* *Whack*!!! > > > > > > > > > > > > > > Signed-off-by: Steven Rostedt > > > > > > > --- > > > > > > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > > > > > > > index fb74dc1f7520..4fa43c02d682 100644 > > > > > > > --- a/drivers/clk/clk.c > > > > > > > +++ b/drivers/clk/clk.c > > > > > > > @@ -682,12 +682,12 @@ static void clk_core_disable(struct clk_core *core) > > > > > > > if (--core->enable_count > 0) > > > > > > > return; > > > > > > > > > > > > > > - trace_clk_disable(core); > > > > > > > + trace_clk_disable_rcuidle(core); > > > > > > > > > > > > > > if (core->ops->disable) > > > > > > > core->ops->disable(core->hw); > > > > > > > > > > > > > > - trace_clk_disable_complete(core); > > > > > > > + trace_clk_disable_complete_rcuidle(core); > > > > > > > > > > > > > > clk_core_disable(core->parent); > > > > > > > } > > > > > > > > > > > > Now the mole shows up here! > > > > > > > > > > And the patch shows up here! > > > > > > > > And I bet you will need this one as well... > > > > > > OK and now the mode is coming back after a short nap during idle: > > > > Seems a bit unfair to whack it just after a short nap, but here goes! > > This mode seems pretty hard headed :) Now clk_core_enable: Nah, just a lot of heads... Thanx, Paul ------------------------------------------------------------------------ commit 21c3fc2373886a9fa014f0f69a72186377758f4b Author: Paul E. McKenney Date: Tue Apr 26 14:02:23 2016 -0700 arm: Whack an expected event-trace-from-idle mole This commit fixes the RCU use-from-idle bug corresponding the following splat: > [ INFO: suspicious RCU usage. ] > 4.6.0-rc5-next-20160426+ #1127 Not tainted > ------------------------------- > include/trace/events/clk.h:45 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 0 > RCU used illegally from extended quiescent state! > 2 locks held by swapper/0/0: > #0: (&oh->hwmod_key#30){......}, at: [] omap_hwmod_enable+0x18/0x44 > #1: (enable_lock){......}, at: [] clk_enable_lock+0x18/0x124 > > stack backtrace: > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.6.0-rc5-next-20160426+ #1127 > Hardware name: Generic OMAP36xx (Flattened Device Tree) > [] (unwind_backtrace) from [] (show_stack+0x10/0x14) > [] (show_stack) from [] (dump_stack+0xb0/0xe4) > [] (dump_stack) from [] (clk_core_enable+0x1e0/0x36c) > [] (clk_core_enable) from [] (clk_enable+0x1c/0x38) > [] (clk_enable) from [] (_enable_clocks+0x18/0x7c) > [] (_enable_clocks) from [] (_enable+0x114/0x2ec) > [] (_enable) from [] (omap_hwmod_enable+0x24/0x44) > [] (omap_hwmod_enable) from [] (omap_device_enable+0x3c/0x90) > [] (omap_device_enable) from [] (_od_runtime_resume+0x10/0x38) > [] (_od_runtime_resume) from [] (__rpm_callback+0x2c/0x60) > [] (__rpm_callback) from [] (rpm_callback+0x20/0x80) > [] (rpm_callback) from [] (rpm_resume+0x3d0/0x6f0) > [] (rpm_resume) from [] (__pm_runtime_resume+0x4c/0x64) > [] (__pm_runtime_resume) from [] (omap2_gpio_resume_after_idle+0x54/0x68) > [] (omap2_gpio_resume_after_idle) from [] (omap3_enter_idle_bm+0xfc/0x1ec) > [] (omap3_enter_idle_bm) from [] (cpuidle_enter_state+0x80/0x3d4) > [] (cpuidle_enter_state) from [] (cpu_startup_entry+0x198/0x3a0) > [] (cpu_startup_entry) from [] (start_kernel+0x354/0x3c8) > [] (start_kernel) from [<8000807c>] (0x8000807c) Reported-by: Tony Lindgren Signed-off-by: Paul E. McKenney Cc: Tony Lindgren Cc: Russell King Cc: Steven Rostedt Cc: Cc: diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 4fa43c02d682..ec83f404c1d2 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -735,12 +735,12 @@ static int clk_core_enable(struct clk_core *core) if (ret) return ret; - trace_clk_enable(core); + trace_clk_enable_rcuidle(core); if (core->ops->enable) ret = core->ops->enable(core->hw); - trace_clk_enable_complete(core); + trace_clk_enable_complete_rcuidle(core); if (ret) { clk_core_disable(core->parent);