Messages in this thread | | | Date | Thu, 16 May 2019 12:05:29 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH] tracing: Kernel access to Ftrace instances |
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Hi,
On Wed, 15 May 2019 18:51:23 -0700 Divya Indi <divya.indi@oracle.com> wrote:
> Hi Masami, > > Thanks for pointing it out. > > Yes, it should not be static. > > On 5/15/19 5:09 PM, Masami Hiramatsu wrote: > > HI Divya, > > > > On Wed, 20 Mar 2019 11:28:51 -0700 > > Divya Indi <divya.indi@oracle.com> wrote: > > > >> Ftrace provides the feature “instances” that provides the capability to > >> create multiple Ftrace ring buffers. However, currently these buffers > >> are created/accessed via userspace only. The kernel APIs providing these > >> features are not exported, hence cannot be used by other kernel > >> components. > >> > >> This patch aims to extend this infrastructure to provide the > >> flexibility to create/log/remove/ enable-disable existing trace events > >> to these buffers from within the kernel. > >> > >> Signed-off-by: Divya Indi <divya.indi@oracle.com> > >> Reviewed-by: Joe Jin <joe.jin@oracle.com> > > Would you tested these APIs with your module? Since, > > [...] > >> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > >> index 5b3b0c3..81c038e 100644 > >> --- a/kernel/trace/trace_events.c > >> +++ b/kernel/trace/trace_events.c > >> @@ -832,6 +832,7 @@ static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set) > >> > >> return ret; > >> } > >> +EXPORT_SYMBOL_GPL(ftrace_set_clr_event); > > I found this exports a static function to module. Did it work? > > I had tested the changes with my module. This change to static was added > in the test patch, but somehow missed it in the final patch that was > sent out.
If you can send some example module patch under samples/, that is more helpful for us to check it. And it is possible to use in kselftest too.
> > Will send a new patch along with a few additional ones to add some NULL > checks to ensure safe usage by modules and add the APIs to a header file > that can be used by the modules.
It seems your's already in Steve's ftrace/core branch, so I think you can make additional patch to fix it. Steve, is that OK?
Thank you,
> > Thanks, > > Divya > > > > > Thank you, > >
-- Masami Hiramatsu <mhiramat@kernel.org>
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