Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 16 Aug 2022 10:14:45 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc:     akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com,
        kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-hyperv@vger.kernel.org, netdev@vger.kernel.org,
        x86@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net,
        halves@canonical.com, fabiomirmar@gmail.com,
        alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com,
        arnd@arndb.de, bp@alien8.de, corbet@lwn.net,
        d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com,
        dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org,
        mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com,
        jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org,
        luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com,
        paulmck@kernel.org, peterz@infradead.org, senozhatsky@chromium.org,
        stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com,
        vkuznets@redhat.com, will@kernel.org,
        Sergei Shtylyov <sergei.shtylyov@gmail.com>
Subject: Re: [PATCH v2 08/13] tracing: Improve panic/die notifiers
Message-ID: <20220816101445.184ebb7c@gandalf.local.home>
In-Reply-To: <20220719195325.402745-9-gpiccoli@igalia.com>
References: <20220719195325.402745-1-gpiccoli@igalia.com>
        <20220719195325.402745-9-gpiccoli@igalia.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Tue, 19 Jul 2022 16:53:21 -0300
"Guilherme G. Piccoli" <gpiccoli@igalia.com> wrote:


Sorry for the late review, but this fell to the bottom of my queue :-/

> +/*
> + * The idea is to execute the following die/panic callback early, in order
> + * to avoid showing irrelevant information in the trace (like other panic
> + * notifier functions); we are the 2nd to run, after hung_task/rcu_stall
> + * warnings get disabled (to prevent potential log flooding).
> + */
> +static int trace_die_panic_handler(struct notifier_block *self,
> +				unsigned long ev, void *unused)
> +{
> +	if (!ftrace_dump_on_oops)
> +		goto out;
> +
> +	if (self == &trace_die_notifier && ev != DIE_OOPS)
> +		goto out;

I really hate gotos that are not for clean ups.

> +
> +	ftrace_dump(ftrace_dump_on_oops);
> +
> +out:
> +	return NOTIFY_DONE;
> +}
> +

Just do:

static int trace_die_panic_handler(struct notifier_block *self,
				unsigned long ev, void *unused)
{
	if (!ftrace_dump_on_oops)
		return NOTIFY_DONE;

	/* The die notifier requires DIE_OOPS to trigger */
	if (self == &trace_die_notifier && ev != DIE_OOPS)
		return NOTIFY_DONE;

	ftrace_dump(ftrace_dump_on_oops);

	return NOTIFY_DONE;
}


Thanks,

Other than that, Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve