Messages in this thread | | | Date | Wed, 26 Feb 2014 13:46:13 -0500 | From | Steven Rostedt <> | Subject | Re: [RFC][PATCH] tracing: Warn and notify if tracepoints are not loaded due to module taint |
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On Wed, 26 Feb 2014 17:24:47 +0000 (UTC) Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote:
> ----- Original Message ----- > > From: "Steven Rostedt" <rostedt@goodmis.org> > > To: "Mathieu Desnoyers" <mathieu.desnoyers@efficios.com> > > Cc: "Peter Zijlstra" <peterz@infradead.org>, "LKML" <linux-kernel@vger.kernel.org>, "Ingo Molnar" <mingo@kernel.org>, > > "Rusty Russell" <rusty@rustcorp.com.au>, "Frederic Weisbecker" <fweisbec@gmail.com>, "Andrew Morton" > > <akpm@linux-foundation.org> > > Sent: Wednesday, February 26, 2014 11:15:42 AM > > Subject: Re: [RFC][PATCH] tracing: Warn and notify if tracepoints are not loaded due to module taint > > > > On Wed, 26 Feb 2014 12:48:12 +0000 (UTC) > > Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote: > > > > > > How about instead of a WARN, you use a normal KERN_ERR printk(). There's > > > > no point to the entire WARN state dump, that's needlessly verbose. > > > > > > > > When you have a normal error print you can have as many as are required > > > > and put the mod name back in. > > > > > > The good old printk KERN_ERR is a very good idea. I agree that WARN() is > > > too verbose for our needs here. > > > > Actually, it's not so bad for the WARN() after my last patch to only > > allocate (or even process tracepoints) if mod->num_tracepionts is > > greater than zero. I didn't realize you were wasting memory for all > > modules that were loaded. > > > > My fear with the KERN_ERR is that it wont be noticeable enough. Where > > as a stack dump is something that will catch people's attention. > > > > And as Rusty has said, if you are loading a module that is forced, or > > something strange, it is broken. The failure of loading the tracepoints > > of a module is a bug if the module happens to have tracepoints. > > > > After the MOD_SIG fix, any failure should be a big banner bug. Either > > they are using a forced module with tracepoints that should not be > > loaded. Or they have tracepoints is a non-GPL module (which is also a > > big no-no). > > Agreed that after the skip for modules containing 0 tracepoints, it gets > much more specific. I like that. > > So then a WARN_ON() that prints the specific module name involved would > be the way to go ?
OK, I have a series of patches to fix a lot of these problems that I will be posting soon. I'm fine with either a WARN() here (with module name) or just a pr_err(). Which of theses do others think is the proper answer?
Peter, Rusty, Andrew?
-- Steve
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