Re: [PATCH 2/2] ftrace: prevent preemption in perf_ftrace_function_call()

2021-10-12 Thread 王贇
On 2021/10/12 下午7:20, Peter Zijlstra wrote: > On Tue, Oct 12, 2021 at 01:40:31PM +0800, 王贇 wrote: > >> diff --git a/kernel/trace/trace_event_perf.c >> b/kernel/trace/trace_event_perf.c >> index 6aed10e..33c2f76 100644 >> --- a/kernel/trace/trace_event_perf.c >> +++

Re: [PATCH 2/2] ftrace: prevent preemption in perf_ftrace_function_call()

2021-10-12 Thread Peter Zijlstra
On Tue, Oct 12, 2021 at 01:40:31PM +0800, 王贇 wrote: > diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c > index 6aed10e..33c2f76 100644 > --- a/kernel/trace/trace_event_perf.c > +++ b/kernel/trace/trace_event_perf.c > @@ -441,12 +441,19 @@ void

[PATCH 2/2] ftrace: prevent preemption in perf_ftrace_function_call()

2021-10-12 Thread 王贇
With CONFIG_DEBUG_PREEMPT we observed reports like: BUG: using smp_processor_id() in preemptible caller is perf_ftrace_function_call+0x6f/0x2e0 CPU: 1 PID: 680 Comm: a.out Not tainted Call Trace: dump_stack_lvl+0x8d/0xcf check_preemption_disabled+0x104/0x110 ?