Ingo, Please merge this patch to your tree. It is a bug fix of irq_vector tracepoints patch.
Seiji > -----Original Message----- > From: Steven Rostedt [mailto:rost...@goodmis.org] > Sent: Friday, June 28, 2013 2:16 PM > To: Seiji Aguchi > Cc: linux-kernel@vger.kernel.org; x...@kernel.org; h...@zytor.com; > mi...@elte.hu; t...@linutronix.de > Subject: Re: [PATCH -tip] x86,trace: Add irq_enter/exit() in > smp_trace_reschedule_interrupt() > > On Fri, 2013-06-28 at 14:02 -0400, Seiji Aguchi wrote: > > Reschedule vector tracepoints may be called in cpu idle state. > > This causes lockdep check warning below. > > > > The tracepoint requires rcu but for accuracy it also > > requires irq_enter() (tracepoints record the irq context), thus, the > > tracepoint interrupt handler should be calling irq_enter() and not > > rcu_irq_enter() (irq_enter() calls rcu_irq_enter()). > > > > So, add irq_enter/exit() to smp_trace_reschedule_interrupt() > > with common pre/post processing functions, smp_entering_irq() > > and exiting_irq() (exiting_irq() calls just irq_exit() > > in arch/x86/include/asm/apic.h), > > because these can be shared among reschedule, call_function, > > and call_function_single vectors. > > > > [ 50.720557] Testing event reschedule_exit: > > [ 50.721349] > > [ 50.721502] =============================== > > [ 50.721835] [ INFO: suspicious RCU usage. ] > > [ 50.722169] 3.10.0-rc6-00004-gcf910e8 #190 Not tainted > > [ 50.722582] ------------------------------- > > [ 50.722915] > > /c/kernel-tests/src/linux/arch/x86/include/asm/trace/irq_vectors.h:50 > > suspicious rcu_dereference_check() usage! > > [ 50.723770] > > [ 50.723770] other info that might help us debug this: > > [ 50.723770] > > [ 50.724385] > > [ 50.724385] RCU used illegally from idle CPU! > > [ 50.724385] rcu_scheduler_active = 1, debug_locks = 0 > > [ 50.725232] RCU used illegally from extended quiescent state! > > [ 50.725690] no locks held by swapper/0/0. > > [ 50.726010] > > [ 50.726010] stack backtrace: > > [ 50.726359] CPU: 0 PID: 0 Comm: swapper/0 Not tainted > > 3.10.0-rc6-00004-gcf910e8 #190 > > [ 50.726965] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > > > > [ 50.727417] 00000001 00000001 79c53f04 798bd9f9 79c53f2c 79077a70 > > 79b412c6 79b41fd1 > > [ 50.728159] 00000001 00000000 79c5ef8c 87147c58 00000000 79c55800 > > 79c53f38 79010b65 > > [ 50.728849] 79c52000 79c53f7c 798c720e 79c52000 79c5ef8c 00000004 > > 00000000 79c55800 > > [ 50.729532] Call Trace: > > [ 50.729730] [<798bd9f9>] dump_stack+0x16/0x18 > > [ 50.730072] [<79077a70>] lockdep_rcu_suspicious+0xf2/0xfa > > [ 50.730498] [<79010b65>] smp_trace_reschedule_interrupt+0x1c8/0x1d0 > > [ 50.730979] [<798c720e>] trace_reschedule_interrupt+0x36/0x3c > > [ 50.731214] [<7901875f>] ? native_safe_halt+0x5/0x7 > > [ 50.731214] [<790085cc>] default_idle+0xb1/0x1e2 > > [ 50.731214] [<79008d05>] arch_cpu_idle+0xe/0x10 > > [ 50.731214] [<79069ddf>] cpu_startup_entry+0x1e4/0x2c3 > > [ 50.731214] [<798adb34>] rest_init+0x12c/0x132 > > [ 50.731214] [<798ada08>] ? __read_lock_failed+0x14/0x14 > > [ 50.731214] [<79d309e4>] start_kernel+0x38d/0x393 > > [ 50.731214] [<79d30489>] ? repair_env_string+0x51/0x51 > > [ 50.731214] [<79d302c3>] i386_start_kernel+0x79/0x7d > > [ 50.771947] OK > > [ 50.772099] Testing event reschedule_entry: OK > > > > Signed-off-by: Seiji Aguchi <seiji.agu...@hds.com> > > Reviewed-by: Steven Rostedt <rost...@goodmis.org> > > -- Steve >
