Re: Possible broken MM code in dell-laptop.c?

From: Darren Hart <dvhart@infradead.org>
To: "Pali Rohár" <pali.rohar@gmail.com>
Cc: Hans de Goede <hdegoede@redhat.com>,
	Ben Skeggs <bskeggs@redhat.com>,
	Stuart Hayes <stuart_hayes@dell.com>,
	Matthew Garrett <mjg@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.cz>,
	platform-driver-x86@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: Possible broken MM code in dell-laptop.c?
Date: Mon, 15 Jun 2015 13:36:45 -0700	[thread overview]
Message-ID: <20150615203645.GD83198@vmdeb7> (raw)
In-Reply-To: <201506141105.07171@pali>

On Sun, Jun 14, 2015 at 11:05:07AM +0200, Pali Rohár wrote:
> Hello,
> 
> in drivers/platform/x86/dell-laptop.c is this part of code:
> 
> static int __init dell_init(void)
> {
> ...
> 	/*
> 	 * Allocate buffer below 4GB for SMI data--only 32-bit physical addr
> 	 * is passed to SMI handler.
> 	 */
> 	bufferpage = alloc_page(GFP_KERNEL | GFP_DMA32);
> 	if (!bufferpage) {
> 		ret = -ENOMEM;
> 		goto fail_buffer;
> 	}
> 	buffer = page_address(bufferpage);
> 
> 	ret = dell_setup_rfkill();
> 
> 	if (ret) {
> 		pr_warn("Unable to setup rfkill\n");
> 		goto fail_rfkill;
> 	}
> ...
> fail_rfkill:
> 	free_page((unsigned long)bufferpage);
> fail_buffer:
> ...
> }
> 
> Then there is another part:
> 
> static void __exit dell_exit(void)
> {
> ...
> 	free_page((unsigned long)buffer);

I believe you are correct, and this should be bufferpage. Have you observed any
failures?

-- 
Darren Hart
Intel Open Source Technology Center