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Message-Id: <201506152242.30732@pali>
Date: Mon, 15 Jun 2015 22:42:30 +0200
From: Pali Rohár <pali.rohar@...il.com>
To: Darren Hart <dvhart@...radead.org>
Cc: Hans de Goede <hdegoede@...hat.com>,
Ben Skeggs <bskeggs@...hat.com>,
Stuart Hayes <stuart_hayes@...l.com>,
Matthew Garrett <mjg@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Michal Hocko <mhocko@...e.cz>,
platform-driver-x86@...r.kernel.org, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, Pavel Machek <pavel@....cz>
Subject: Re: Possible broken MM code in dell-laptop.c?
On Monday 15 June 2015 22:36:45 Darren Hart wrote:
> 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?
Rmmoding dell-laptop.ko works fine. There is no error in dmesg. I think
that buffer (and not bufferpage) should be passed to free_page(). So in
my opinion problem is at fail_rfkill: label and not in dell_exit().
But somebody from linux-mm should look at it...
--
Pali Rohár
pali.rohar@...il.com
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