From: Steven Rostedt <rostedt@goodmis.org>
To: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: Stephen Boyd <sboyd@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Andy Gross <andy.gross@linaro.org>,
David Brown <david.brown@linaro.org>,
Jiri Slaby <jslaby@suse.com>,
"Ivan T. Ivanov" <ivan.ivanov@linaro.org>,
Kees Cook <keescook@chromium.org>,
"Joel Fernandes (Google)" <joel@joelfernandes.org>,
Geliang Tang <geliangtang@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Pramod Gurav <gpramod@codeaurora.org>,
linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org,
linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
Rajendra Nayak <rnayak@codeaurora.org>,
Vivek Gautam <vivek.gautam@codeaurora.org>,
Sibi Sankar <sibis@codeaurora.org>
Subject: Re: Crash in msm serial on dragonboard with ftrace bootargs
Date: Tue, 16 Oct 2018 12:57:21 -0400 [thread overview]
Message-ID: <20181016125721.236ada82@gandalf.local.home> (raw)
In-Reply-To: <8c2fb318-813d-81f1-1e2f-cdbc68353077@codeaurora.org>
On Tue, 16 Oct 2018 22:05:23 +0530
Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> wrote:
> On 10/16/2018 8:59 PM, Steven Rostedt wrote:
> > On Tue, 16 Oct 2018 17:08:25 +0530
> > Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> wrote:
> >
> >> Hi,
> >>
> >> On dragonboard 410c, with "ftrace=function" boot args, the console
> >> output slows down and board resets without any backtrace as below. This
> >> is tested on latest kernel and seems to exist even in older kernels as well.
> >
> > So this only happens when ftrace=function is on the boot console.
> >
>
> Yes. If I do not use boot console, target does not crash.
>
> >
> > Does function tracing work after boot up? That is, without the
> > ftrace=function, can you do:
> >
> > echo function > /sys/kernel/debug/tracing/current_tracer
> >
> > without any issue?
> >
>
> Yes ftrace in general works without any issue. I have also tested on
> db820c and sdm845 where "ftrace=function" works fine. I am seeing this
> issue only on db410c board.
OK, can you add to the command line:
ftrace=function ftrace_filter=*schedule*
to see if it's a specific function that may be causing the issue (but
hopefully it's not one of the scheduling functions that caused it).
>
> >>
> >> One more thing is for pstore dmesg-ramoops, I had to change
> >> late_initcall to postcore_initcall which brings the question as to why
> >> we changed to late_initcall?
> >> Simple git blame shows to support crypto compress api, but is it really
> >> helpful? A lot of boottime issues can be caught with pstore enabled at
> >> postcore_initcall rather than late_initcall, this backtrace
> >> is just one example. Is there any way we could change this?
> >
> > Does it break if the crypto is not initialized? Perhaps add a command
> > line flag to have it happen earlier:
> >
>
> I didnt see any breakage, have been using ramoops with postcore_initcall
> for sometime now.
>
> > ramoops=earlyinit
> >
> > and add a postcore_initcall that checks if that flag is set, and if so,
> > it does the work then, and the late_initcall() will do nothing.
> >
> > That way, you can still have unmodified kernels use pstore when it
> > crashes at boot up.
> >
>
> Sounds good.
Great, I guess you can write a patch to do that ;-)
-- Steve
next prev parent reply other threads:[~2018-10-16 16:57 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-16 11:38 Crash in msm serial on dragonboard with ftrace bootargs Sai Prakash Ranjan
2018-10-16 11:44 ` Greg Kroah-Hartman
2018-10-16 11:58 ` Sai Prakash Ranjan
2018-10-16 15:29 ` Steven Rostedt
2018-10-16 16:35 ` Sai Prakash Ranjan
2018-10-16 16:57 ` Steven Rostedt [this message]
2018-10-16 17:36 ` Sai Prakash Ranjan
2018-10-16 17:48 ` Steven Rostedt
2018-10-16 18:05 ` Sai Prakash Ranjan
2018-10-16 18:16 ` Steven Rostedt
2018-10-16 18:25 ` Sai Prakash Ranjan
2018-10-16 18:41 ` Steven Rostedt
2018-10-16 19:01 ` Sai Prakash Ranjan
2018-10-16 19:03 ` Steven Rostedt
2018-10-16 19:06 ` Sai Prakash Ranjan
2018-10-16 19:15 ` Steven Rostedt
2018-10-16 19:16 ` Steven Rostedt
2018-10-16 19:37 ` Sai Prakash Ranjan
2018-10-16 19:35 ` Sai Prakash Ranjan
2018-10-16 20:51 ` Stephen Boyd
2018-10-17 11:27 ` Sai Prakash Ranjan
2018-10-18 2:33 ` Steven Rostedt
2018-10-18 5:21 ` Sai Prakash Ranjan
2018-10-18 13:17 ` Steven Rostedt
2018-10-19 4:17 ` Joel Fernandes
2018-10-19 6:54 ` Sai Prakash Ranjan
2018-10-19 13:51 ` Steven Rostedt
2018-10-19 14:48 ` Sai Prakash Ranjan
2018-10-19 15:12 ` Steven Rostedt
2018-10-25 14:36 ` saiprakash.ranjan
2018-11-13 9:44 ` Srinivas Kandagatla
2018-11-15 10:33 ` Sai Prakash Ranjan
2018-11-15 10:53 ` Srinivas Kandagatla
2018-11-16 3:39 ` Viresh Kumar
2018-11-16 10:49 ` Sai Prakash Ranjan
2018-10-16 17:02 ` Kees Cook
2018-10-17 10:13 ` Joel Fernandes
2018-10-17 11:38 ` Sai Prakash Ranjan
2018-10-17 14:49 ` Sai Prakash Ranjan
2018-10-17 17:56 ` Joel Fernandes
2018-10-17 18:25 ` Kees Cook
2018-10-16 23:09 ` Joel Fernandes
2018-10-17 11:53 ` Sai Prakash Ranjan
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