| Subject: trace: Use rcuidle version for preemptoff_hist trace point |
| From: Yang Shi <yang.shi@windriver.com> |
| Date: Tue, 23 Feb 2016 13:23:23 -0800 |
| |
| When running -rt kernel with both PREEMPT_OFF_HIST and LOCKDEP enabled, |
| the below error is reported: |
| |
| [ INFO: suspicious RCU usage. ] |
| 4.4.1-rt6 #1 Not tainted |
| include/trace/events/hist.h:31 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! |
| no locks held by swapper/0/0. |
| |
| stack backtrace: |
| CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.1-rt6-WR8.0.0.0_standard #1 |
| Stack : 0000000000000006 0000000000000000 ffffffff81ca8c38 ffffffff81c8fc80 |
| ffffffff811bdd68 ffffffff81cb0000 0000000000000000 ffffffff81cb0000 |
| 0000000000000000 0000000000000000 0000000000000004 0000000000000000 |
| 0000000000000004 ffffffff811bdf50 0000000000000000 ffffffff82b60000 |
| 0000000000000000 ffffffff812897ac ffffffff819f0000 000000000000000b |
| ffffffff811be460 ffffffff81b7c588 ffffffff81c8fc80 0000000000000000 |
| 0000000000000000 ffffffff81ec7f88 ffffffff81d70000 ffffffff81b70000 |
| ffffffff81c90000 ffffffff81c3fb00 ffffffff81c3fc28 ffffffff815e6f98 |
| 0000000000000000 ffffffff81c8fa87 ffffffff81b70958 ffffffff811bf2c4 |
| 0707fe32e8d60ca5 ffffffff81126d60 0000000000000000 0000000000000000 |
| ... |
| Call Trace: |
| [<ffffffff81126d60>] show_stack+0xe8/0x108 |
| [<ffffffff815e6f98>] dump_stack+0x88/0xb0 |
| [<ffffffff8124b88c>] time_hardirqs_off+0x204/0x300 |
| [<ffffffff811aa5dc>] trace_hardirqs_off_caller+0x24/0xe8 |
| [<ffffffff811a4ec4>] cpu_startup_entry+0x39c/0x508 |
| [<ffffffff81d7dc68>] start_kernel+0x584/0x5a0 |
| |
| Replace regular trace_preemptoff_hist to rcuidle version to avoid the error. |
| |
| Signed-off-by: Yang Shi <yang.shi@windriver.com> |
| Cc: bigeasy@linutronix.de |
| Cc: rostedt@goodmis.org |
| Cc: linux-rt-users@vger.kernel.org |
| Link: http://lkml.kernel.org/r/1456262603-10075-1-git-send-email-yang.shi@windriver.com |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| --- |
| I recall the rcuidle version is used by 4.1-rt, but not sure why it is dropped |
| in 4.4-rt. It looks such fix is still needed. |
| |
| kernel/trace/trace_irqsoff.c | 8 ++++---- |
| 1 file changed, 4 insertions(+), 4 deletions(-) |
| |
| --- a/kernel/trace/trace_irqsoff.c |
| +++ b/kernel/trace/trace_irqsoff.c |
| @@ -425,13 +425,13 @@ void start_critical_timings(void) |
| { |
| if (preempt_trace() || irq_trace()) |
| start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); |
| - trace_preemptirqsoff_hist(TRACE_START, 1); |
| + trace_preemptirqsoff_hist_rcuidle(TRACE_START, 1); |
| } |
| EXPORT_SYMBOL_GPL(start_critical_timings); |
| |
| void stop_critical_timings(void) |
| { |
| - trace_preemptirqsoff_hist(TRACE_STOP, 0); |
| + trace_preemptirqsoff_hist_rcuidle(TRACE_STOP, 0); |
| if (preempt_trace() || irq_trace()) |
| stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); |
| } |
| @@ -441,7 +441,7 @@ EXPORT_SYMBOL_GPL(stop_critical_timings) |
| #ifdef CONFIG_PROVE_LOCKING |
| void time_hardirqs_on(unsigned long a0, unsigned long a1) |
| { |
| - trace_preemptirqsoff_hist(IRQS_ON, 0); |
| + trace_preemptirqsoff_hist_rcuidle(IRQS_ON, 0); |
| if (!preempt_trace() && irq_trace()) |
| stop_critical_timing(a0, a1); |
| } |
| @@ -450,7 +450,7 @@ void time_hardirqs_off(unsigned long a0, |
| { |
| if (!preempt_trace() && irq_trace()) |
| start_critical_timing(a0, a1); |
| - trace_preemptirqsoff_hist(IRQS_OFF, 1); |
| + trace_preemptirqsoff_hist_rcuidle(IRQS_OFF, 1); |
| } |
| |
| #else /* !CONFIG_PROVE_LOCKING */ |