From mboxrd@z Thu Jan 1 00:00:00 1970 From: paulmck@linux.vnet.ibm.com (Paul E. McKenney) Date: Tue, 26 Apr 2016 12:47:37 -0700 Subject: [PATCH arm 1/1] arm: Use _rcuidle tracepoint to allow use from idle In-Reply-To: <20160426193949.GP5995@atomide.com> References: <1461617335-22372-1-git-send-email-paulmck@linux.vnet.ibm.com> <20160426150031.GP5995@atomide.com> <20160426175214.GJ3715@linux.vnet.ibm.com> <20160426182939.GO5995@atomide.com> <20160426190755.GK3715@linux.vnet.ibm.com> <20160426193949.GP5995@atomide.com> Message-ID: <20160426194737.GM3715@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 12:39:50PM -0700, Tony Lindgren wrote: > * Paul E. McKenney [160426 12:08]: > > On Tue, Apr 26, 2016 at 11:29:39AM -0700, Tony Lindgren wrote: > > > * Paul E. McKenney [160426 10:53]: > > > > Does the following patch help? > > > > > > It just changes the output.. See below. > > > > Ah -- you need both patches. > > Oops sorry, I though I had the first one already from next.. > > > These are on -rcu at: > > > > 501889db6fee (arm: Use _rcuidle tracepoint to allow use from idle) > > 99cd56ad86d2 (rm: Use more _rcuidle tracepoints to allow use from idle) > > With these omap4 is now OK. But omap3 produces yet another warning, > See below :) As Steven Rostedt said, whack-a-mole time... The previous two patches are still needed. Thanx, Paul ------------------------------------------------------------------------ commit c7ab21af6d959e3541ea52427472fc5dece75023 Author: Paul E. McKenney Date: Tue Apr 26 12:43:57 2016 -0700 arm: Additional _rcuidle tracepoints to allow use from idle This commit adds an _rcuidle suffix to a pair of trace events to prevent the following splat: > =============================== > [ INFO: suspicious RCU usage. ] > 4.6.0-rc5-next-20160426+ #1114 Not tainted > ------------------------------- > include/trace/events/clk.h:59 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_idle+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+ #1114 > 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_disable+0x17c/0x348) > [] (clk_core_disable) from [] (clk_disable+0x24/0x30) > [] (clk_disable) from [] (_disable_clocks+0x18/0x7c) > [] (_disable_clocks) from [] (_idle+0x12c/0x230) > [] (_idle) from [] (omap_hwmod_idle+0x24/0x44) > [] (omap_hwmod_idle) from [] (omap_device_idle+0x3c/0x90) > [] (omap_device_idle) from [] (__rpm_callback+0x2c/0x60) > [] (__rpm_callback) from [] (rpm_callback+0x20/0x80) > [] (rpm_callback) from [] (rpm_suspend+0x100/0x768) > [] (rpm_suspend) from [] (__pm_runtime_suspend+0x64/0x84) > [] (__pm_runtime_suspend) from [] (omap2_gpio_prepare_for_idle+0x5 > c/0x70) > [] (omap2_gpio_prepare_for_idle) from [] (omap_sram_idle+0x140/0x2 > 44) > [] (omap_sram_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 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); }