From: Steven Rostedt <rostedt@goodmis.org>
To: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: Ingo Molnar <mingo@redhat.com>, Laura Abbott <labbott@redhat.com>,
Kees Cook <keescook@chromium.org>,
Anton Vorontsov <anton@enomsg.org>,
Rob Herring <robh+dt@kernel.org>,
devicetree@vger.kernel.org, Colin Cross <ccross@android.com>,
Jason Baron <jbaron@akamai.com>, Tony Luck <tony.luck@intel.com>,
Arnd Bergmann <arnd@arndb.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Joel Fernandes <joel@joelfernandes.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Joe Perches <joe@perches.com>, Jim Cromie <jim.cromie@gmail.com>,
Rajendra Nayak <rnayak@codeaurora.org>,
Vivek Gautam <vivek.gautam@codeaurora.org>,
Sibi Sankar <sibis@codeaurora.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@kernel.org>,
Tom Zanussi <tom.zanussi@linux.intel.com>,
Prasad Sodagudi <psodagud@codeaurora.org>,
tsoni@codeaurora.org, Bryan Huntsman <bryanh@codeaurora.org>,
Tingwei Zhang <tingwei@codeaurora.org>
Subject: Re: [PATCH 2/6] pstore: Add event tracing support
Date: Tue, 18 Sep 2018 16:44:34 -0400 [thread overview]
Message-ID: <20180918164434.472294f3@gandalf.local.home> (raw)
In-Reply-To: <cb17a8c9-fca1-5492-3255-eab0ea33577c@codeaurora.org>
On Tue, 18 Sep 2018 23:22:48 +0530
Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> wrote:
> On 9/18/2018 5:04 AM, Steven Rostedt wrote:
> >
> > It looks like pstore_event_call() gets called from a trace event. You
> > can't call kmalloc() from one. One thing is that kmalloc has
> > tracepoints itself. You trace those you just entered an infinite loop.
> >
> >
>
> Ok will remove it in v2. But any alternative way to do this?
I think I describe it below.
>
> >> +
> >> + event_call = fbuffer->trace_file->event_call;
> >> + if (!event_call || !event_call->event.funcs ||
> >> + !event_call->event.funcs->trace)
> >> + goto fail_event;
> >> +
> >> + event = &fbuffer->trace_file->event_call->event;
> >> +
> >> + spin_lock_irqsave(&psinfo->buf_lock, flags);
> >> +
> >> + trace_seq_init(&iter->seq);
> >> + iter->ent = fbuffer->entry;
> >
> > I guess what you are doing is needing to translate the raw data into
> > ascii output, and need the trace_iterator to do so.
> >
> > You are already under a psinfo->buf_lock. Add a dummy iterator to that
> > and use it instead.
> >
> > trace_seq_init(&psinfo->iter->seq);
> >
> >> + event_call->event.funcs->trace(iter, 0, event);
> >
> > (psinfo->iter, 0 , event);
> >
> > etc.
> >
>
> Sure, will update in v2.
>
> >> + trace_seq_putc(&iter->seq, 0);
> >> +
> >> + if (seq->size > psinfo->bufsize)
> >> + seq->size = psinfo->bufsize;
> >> +
> >> + s = &iter->seq;
> >> + seq = &s->seq;
> >> +
> >> + record.buf = (char *)(seq->buffer);
> >> + record.size = seq->len;
> >> + psinfo->write(&record);
> >> +
> >> + spin_unlock_irqrestore(&psinfo->buf_lock, flags);
> >
> > You may also need to convert these spin_locks into raw_spin_locks as
> > when PREEMPT_RT enters the kernel you don't want them to turn into
> > mutexes.
> >
> > But that can be another patch.
> >
>
> I will change this in v2, but can't we have it in same patch?
I suggested a separate patch because buf_lock is used elsewhere.
Changing it to "raw_spin_lock" will affect more than just what this
patch series does. Thus, I recommend making it a separate patch to keep
this patch series from being more intrusive than it needs to be.
Thanks!
-- Steve
next prev parent reply other threads:[~2018-09-18 20:44 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-08 20:27 [PATCH 0/6] Tracing register accesses with pstore and dynamic debug Sai Prakash Ranjan
2018-09-08 20:27 ` [PATCH 1/6] dt-bindings: ramoops: Add event-size property Sai Prakash Ranjan
[not found] ` <5b9f3f67.1c69fb81.3125b.c205@mx.google.com>
2018-09-17 17:15 ` Sai Prakash Ranjan
2018-09-08 20:27 ` [PATCH 2/6] pstore: Add event tracing support Sai Prakash Ranjan
2018-09-11 10:46 ` Sai Prakash Ranjan
2018-09-17 17:38 ` Stephen Boyd
2018-09-17 19:43 ` Sai Prakash Ranjan
2018-09-16 7:07 ` Sai Prakash Ranjan
[not found] ` <CAEXW_YSPNqVgoYWjVAMvGg_WoRV4SC2xDH1wQWTdQfBUOMQbbQ@mail.gmail.com>
2018-09-17 14:54 ` Kees Cook
2018-09-17 17:17 ` Sai Prakash Ranjan
2018-09-17 17:13 ` Sai Prakash Ranjan
2018-09-17 23:04 ` Steven Rostedt
2018-09-18 6:24 ` Sai Prakash Ranjan
2018-09-17 23:34 ` Steven Rostedt
2018-09-18 17:52 ` Sai Prakash Ranjan
2018-09-18 20:44 ` Steven Rostedt [this message]
2018-09-18 21:13 ` Sai Prakash Ranjan
2018-09-22 6:48 ` Sai Prakash Ranjan
2018-09-22 9:05 ` Joel Fernandes
2018-09-22 16:37 ` Sai Prakash Ranjan
2018-09-22 17:32 ` Sai Prakash Ranjan
2018-09-22 17:45 ` Sai Prakash Ranjan
2018-09-23 15:33 ` Sai Prakash Ranjan
2018-09-25 20:37 ` Joel Fernandes
2018-09-25 20:39 ` Joel Fernandes
2018-09-25 20:40 ` Joel Fernandes
2018-09-26 9:52 ` Sai Prakash Ranjan
2018-09-08 20:27 ` [PATCH 3/6] tracing: Add tp_pstore cmdline to have tracepoints go to pstore Sai Prakash Ranjan
2018-09-25 21:25 ` Joel Fernandes
2018-09-26 9:46 ` Sai Prakash Ranjan
2018-10-08 14:16 ` Sai Prakash Ranjan
2018-10-08 14:36 ` Steven Rostedt
2018-10-08 22:40 ` Joel Fernandes
2018-10-09 18:22 ` Sai Prakash Ranjan
2018-10-10 19:37 ` Steven Rostedt
2018-09-08 20:27 ` [PATCH 4/6] arm64/io: Add tracepoint for register accesses Sai Prakash Ranjan
2018-09-08 20:27 ` [PATCH 5/6] arm64/io: Add header for instrumentation of io operations Sai Prakash Ranjan
2018-09-17 23:39 ` Steven Rostedt
2018-09-18 7:10 ` Sai Prakash Ranjan
2018-09-18 11:47 ` Will Deacon
2018-09-18 12:43 ` Sai Prakash Ranjan
2018-09-08 20:27 ` [PATCH 6/6] dynamic_debug: Add flag for dynamic event tracing Sai Prakash Ranjan
2018-09-11 15:11 ` [PATCH 0/6] Tracing register accesses with pstore and dynamic debug Will Deacon
2018-09-11 16:11 ` Sai Prakash Ranjan
2018-10-20 5:25 ` Joel Fernandes
2018-10-20 6:32 ` Sai Prakash Ranjan
2018-10-20 16:27 ` Joel Fernandes
2018-10-21 3:46 ` Sai Prakash Ranjan
2018-10-21 4:59 ` Sai Prakash Ranjan
2018-10-21 5:09 ` Joel Fernandes
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