Hi Masami,
On Thu, Aug 2, 2018 at 7:55 AM, Masami Hiramatsu <mhira...@kernel.org> wrote:
> Hi Joel,
>
> I found this caused several issues when testing ftrace.
>
> #1) ftrace boottest (FTRACE_STARTUP_TEST) fails
This sadly appears to be a real issue. The startup test for
"preemptirqsoff" tracer fails, however it passes for only preemptoff
or only irqsoff. I tested only the last 2 tracers, not the first one,
that's why I didn't catch it. I need to debug this more.
> #2) mmiotrace reports "IRQs not enabled as expected" error
> #3) lock subsystem event boottest causes "IRQs not disabled as expected"
> error (sometimes)
Could you try the below patch and let me know if you still see the
issue? In the v11 I removed the lockdep_recursing() check since it
seemed unnecessary. But I'd like to rule out that there's still some
issue lurking there. Thanks and I appreciate your help, diff is
attached to this email.
> #4) ftracetest test.d/event/toplevel-enable.tc causes "suspicious RCU usage"
> warning
I sent a patch fixing this with you on CC. I tested that it fixes the
issue you're reporting.
diff --git a/kernel/trace/trace_preemptirq.c b/kernel/trace/trace_preemptirq.c
index e76b78bf258e..13e2c6e99465 100644
--- a/kernel/trace/trace_preemptirq.c
+++ b/kernel/trace/trace_preemptirq.c
@@ -19,7 +19,7 @@ static DEFINE_PER_CPU(int, tracing_irq_cpu);
void trace_hardirqs_on(void)
{
- if (!this_cpu_read(tracing_irq_cpu))
+ if (lockdep_recursing(current) || !this_cpu_read(tracing_irq_cpu))
return;
trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
@@ -29,7 +29,7 @@ EXPORT_SYMBOL(trace_hardirqs_on);
void trace_hardirqs_off(void)
{
- if (this_cpu_read(tracing_irq_cpu))
+ if (lockdep_recursing(current) || this_cpu_read(tracing_irq_cpu))
return;
this_cpu_write(tracing_irq_cpu, 1);
@@ -39,7 +39,7 @@ EXPORT_SYMBOL(trace_hardirqs_off);
__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
{
- if (!this_cpu_read(tracing_irq_cpu))
+ if (lockdep_recursing(current) || !this_cpu_read(tracing_irq_cpu))
return;
trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
@@ -49,7 +49,7 @@ EXPORT_SYMBOL(trace_hardirqs_on_caller);
__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
{
- if (this_cpu_read(tracing_irq_cpu))
+ if (lockdep_recursing(current) || this_cpu_read(tracing_irq_cpu))
return;
this_cpu_write(tracing_irq_cpu, 1);
