Re: [PATCH v10 2/9] xen: do not free reserved memory into heap

From: Jan Beulich <jbeulich@suse.com>
To: Penny Zheng <Penny.Zheng@arm.com>
Cc: wei.chen@arm.com, Stefano Stabellini <sstabellini@kernel.org>,
	Julien Grall <julien@xen.org>,
	Bertrand Marquis <bertrand.marquis@arm.com>,
	Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	George Dunlap <george.dunlap@citrix.com>, Wei Liu <wl@xen.org>,
	Julien Grall <jgrall@amazon.com>,
	xen-devel@lists.xenproject.org
Subject: Re: [PATCH v10 2/9] xen: do not free reserved memory into heap
Date: Tue, 16 Aug 2022 08:40:50 +0200	[thread overview]
Message-ID: <6c2d0111-3ac3-83aa-145f-432f5fae0167@suse.com> (raw)
In-Reply-To: <20220816023658.3551936-3-Penny.Zheng@arm.com>

On 16.08.2022 04:36, Penny Zheng wrote:
> +void free_domstatic_page(struct page_info *page)
> +{
> +    struct domain *d = page_get_owner(page);
> +    bool drop_dom_ref;
> +
> +    if ( unlikely(!d) )
> +    {
> +        ASSERT_UNREACHABLE();
> +        printk("The about-to-free static page %"PRI_mfn" must be owned by a domain\n",
> +               mfn_x(page_to_mfn(page)));
> +        return;
> +    }

For the message to be useful as a hint if the assertion triggers, it
wants printing ahead of the assertion. I also think it wants to be a
XENLOG_G_* kind of log level, so it would be rate limited by default
in release builds. Just to be on the safe side. (I'm not in favor of
the log message in the first place, but I do know that Julien had
asked for one.)

Jan