From: Masami Hiramatsu <mhiramat@kernel.org>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Naveen Rao <naveen.n.rao@linux.vnet.ibm.com>,
Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Subject: Re: [for-next][PATCH 7/8] tracing/probe: Reject exactly same probe event
Date: Mon, 23 Sep 2019 10:15:26 -0700 [thread overview]
Message-ID: <20190923101526.a1a9ccde50da83fbdc86aad8@kernel.org> (raw)
In-Reply-To: <20190923102035.GA30095@linux.vnet.ibm.com>
On Mon, 23 Sep 2019 16:12:53 +0530
Srikar Dronamraju <srikar@linux.vnet.ibm.com> wrote:
> Hey Masami, Steven
>
> >
> > +static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
> > + struct trace_kprobe *comp)
> > +{
> > + struct trace_probe_event *tpe = orig->tp.event;
> > + struct trace_probe *pos;
> > + int i;
> > +
> > + list_for_each_entry(pos, &tpe->probes, list) {
> > + orig = container_of(pos, struct trace_kprobe, tp);
> > + if (strcmp(trace_kprobe_symbol(orig),
> > + trace_kprobe_symbol(comp)) ||
> > + trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
> > + continue;
> > +
> > + /*
> > + * trace_probe_compare_arg_type() ensured that nr_args and
> > + * each argument name and type are same. Let's compare comm.
> > + */
> > + for (i = 0; i < orig->tp.nr_args; i++) {
> > + if (strcmp(orig->tp.args[i].comm,
> > + comp->tp.args[i].comm))
> > + continue;
>
> In a nested loop, *continue* is going to continue iterating through the
> inner loop. In which case, continue is doing nothing here. I thought we
> should have used a goto instead. No? To me, continue as a last statement of
> a for loop always looks weird.
Oops, thanks for pointing it out!
>
> > + }
> > +
> > + return true;
> > + }
>
> I think we need something like this:
>
> list_for_each_entry(pos, &tpe->probes, list) {
> orig = container_of(pos, struct trace_kprobe, tp);
> if (strcmp(trace_kprobe_symbol(orig),
> trace_kprobe_symbol(comp)) ||
> trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
> continue;
>
> /*
> * trace_probe_compare_arg_type() ensured that nr_args and
> * each argument name and type are same. Let's compare comm.
> */
> for (i = 0; i < orig->tp.nr_args; i++) {
> if (strcmp(orig->tp.args[i].comm,
> comp->tp.args[i].comm))
> goto outer_loop;
>
> }
>
> return true;
> outer_loop:
> }
Correct, that's what I intended.
Could you make a fix patch on top of it? (or do I?)
Thank you,
>
>
> > +
> > + return false;
> > +}
> > +
> >
>
> ......
>
> > +static bool trace_uprobe_has_same_uprobe(struct trace_uprobe *orig,
> > + struct trace_uprobe *comp)
> > +{
> > + struct trace_probe_event *tpe = orig->tp.event;
> > + struct trace_probe *pos;
> > + struct inode *comp_inode = d_real_inode(comp->path.dentry);
> > + int i;
> > +
> > + list_for_each_entry(pos, &tpe->probes, list) {
> > + orig = container_of(pos, struct trace_uprobe, tp);
> > + if (comp_inode != d_real_inode(orig->path.dentry) ||
> > + comp->offset != orig->offset)
> > + continue;
> > +
> > + /*
> > + * trace_probe_compare_arg_type() ensured that nr_args and
> > + * each argument name and type are same. Let's compare comm.
> > + */
> > + for (i = 0; i < orig->tp.nr_args; i++) {
> > + if (strcmp(orig->tp.args[i].comm,
> > + comp->tp.args[i].comm))
> > + continue;
>
> Same as above.
>
> > + }
> > +
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > +
>
> --
> Thanks and Regards
> Srikar Dronamraju
>
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2019-09-23 17:15 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-19 23:23 [for-next][PATCH 0/8] tracing: Final updates before sending to Linus Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 1/8] ftrace: Simplify ftrace hash lookup code in clear_func_from_hash() Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 2/8] tracing: Be more clever when dumping hex in __print_hex() Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 3/8] tracing: Make sure variable reference alias has correct var_ref_idx Steven Rostedt
[not found] ` <20190921120618.DF81120665@mail.kernel.org>
2019-09-21 12:20 ` Steven Rostedt
2019-09-21 19:21 ` Sasha Levin
2019-09-21 19:23 ` Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 4/8] tracing/kprobe: Fix NULL pointer access in trace_porbe_unlink() Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 5/8] selftests/ftrace: Select an existing function in kprobe_eventname test Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 6/8] tracing/probe: Fix to allow user to enable events on unloaded modules Steven Rostedt
2019-09-19 23:23 ` [for-next][PATCH 7/8] tracing/probe: Reject exactly same probe event Steven Rostedt
2019-09-23 10:42 ` Srikar Dronamraju
2019-09-23 17:15 ` Masami Hiramatsu [this message]
2019-09-23 17:42 ` Srikar Dronamraju
2019-09-19 23:23 ` [for-next][PATCH 8/8] selftests/ftrace: Update kprobe event error testcase Steven Rostedt
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