On Tue, 8 Mar 2016 21:37:01 +0800 Chunyu Hu <[email protected]> wrote:
> But after some tests, find it's not easy to setup tracer flag when > its target is not the current tracer. Some check logic of function > and function_graph trace seems not appropriate now, some WARN in > ftrace.c are triggered. > > kernel: WARNING: CPU: 2 PID: 5522 at kernel/trace/ftrace.c:5106 > ftrace_init_array_ops+0x4a/0x70() > kernel: WARNING: CPU: 2 PID: 5522 at kernel/trace/ftrace.c:413 > ftrace_startup+0x229/0x240() > kernel: WARNING: CPU: 2 PID: 30451 at kernel/trace/ftrace.c:460 > return_to_handler+0x0/0x27() > > Here just forbit it return an invalid code to user space with extra > dmesg help info to avoid the complex WARN log. This is not acceptable. The whole point of making the options visible when the tracer is not active was to change the flags when the tracer is not active. I'll look deeper into this. Thanks. -- Steve
