linux-kernel - Re: [PATCH v2 1/3] livepatch: Add force sysfs attribute

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Message-ID: <20170811211321.uwn4clccx6pjnbxw@treble>
Date:   Fri, 11 Aug 2017 16:13:22 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Miroslav Benes <mbenes@...e.cz>
Cc:     jeyu@...nel.org, jikos@...nel.org, pmladek@...e.com,
        lpechacek@...e.cz, live-patching@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/3] livepatch: Add force sysfs attribute

On Thu, Aug 10, 2017 at 12:48:13PM +0200, Miroslav Benes wrote:
> +static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
> +			   const char *buf, size_t count)
> +{
> +	/*
> +	 * klp_mutex lock is not grabbed here intentionally. It is not really
> +	 * needed. The race window is harmless and grabbing the lock would only
> +	 * hold the action back.
> +	 */
> +	if (!klp_transition_patch) {
> +		pr_info("no patching in progress, forced action ineffective\n");
> +		return -EINVAL;
> +	}
> +
> +	return -EINVAL;
> +}

I think this is really a minor issue, and the -EINVAL is enough.  As the
comment says, the race window is harmless.  So I'd say there's no need
to scare the user with a printk.

-- 
Josh