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Date:   Fri, 19 Jun 2020 08:19:54 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Ming Lei <ming.lei@redhat.com>
Cc:     Masami Hiramatsu <mhiramat@kernel.org>,
        Ming Lei <tom.leiming@gmail.com>,
        "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        linux-block <linux-block@vger.kernel.org>
Subject: Re: kprobe: __blkdev_put probe is missed
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On Fri, 19 Jun 2020 15:28:59 +0800
Ming Lei <ming.lei@redhat.com> wrote:

> > 
> > OK, then let's make events (for sure)
> > 
> > root@devnote2:/sys/kernel/debug/tracing# echo p __blkdev_put >> kprobe_events 
> > root@devnote2:/sys/kernel/debug/tracing# echo r __blkdev_put >> kprobe_events 
> > root@devnote2:/sys/kernel/debug/tracing# echo p blkdev_put >> kprobe_events 

Hi Ming,

Do you have the kprobe_events file?

> > root@devnote2:/sys/kernel/debug/tracing# echo 1 > events/kprobes/enable   
> 
> I can't find 'events/kprobes' in my VM with upstream kernel, also not found
> the dir under fedora31(5.5.15-200) & rhel8(v4.18 based).

The events/kprobes directly will be created when you create a
kprobe_event. It wont exist until then.

-- Steve