linux-kernel - Re: What would cause /proc/ioports do be zeroed out?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87mv9m1dh9.fsf@fencepost.gnu.org>
Date:   Mon, 05 Jun 2017 20:44:18 +0200
From:   David Kastrup <dak@....org>
To:     Randy Dunlap <rdunlap@...radead.org>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: What would cause /proc/ioports do be zeroed out?

Randy Dunlap <rdunlap@...radead.org> writes:

> On 06/05/17 02:08, David Kastrup wrote:
>> 
>> Hi,
>> 
>> I am trying to pinpoint a problem I am having with current Ubuntu
>> Artful, likely after some recent attempts of getting rid of some package
>> incompatibilities.  More likely than not the ultimate culprit is
>> somewhere in the Debian package management, however I am really puzzled
>> at figuring out where exactly things go wrong and since my current
>> configuration is "valid" according to the package manager, it might help
>> in other situations if I manage to get the problem located.
>> 
>> The current symptom is that I cannot load some ACPI modules (compiled
>> via DKMS for x86_64 architecture) without io_force option, with the
>> kernel stating:
>> 
>> [  248.145348] thinkpad_ec: cannot claim IO ports 0x1600-0x161f... 
>> [  248.145350] consider using force_io=1.
>> 
>> Now here is the really fishy thing:
>> 
>> cat /proc/ioports
>> 0000-0000 : PCI Bus 0000:00
>>   0000-0000 : dma1
>>   0000-0000 : pic1
>>   0000-0000 : timer0
>>   0000-0000 : smapi
>>   0000-0000 : timer1
>>   0000-0000 : keyboard
>>   0000-0000 : PNP0800:00
>>   0000-0000 : PNP0C09:00
>>     0000-0000 : EC data
>>   0000-0000 : keyboard
>>   0000-0000 : PNP0C09:00
>>     0000-0000 : EC cmd
>> 
>> [...]
>> 
>>   0000-0000 : PCI Bus 0000:0d
>>   0000-0000 : PCI Bus 0000:15
>>     0000-0000 : PCI CardBus 0000:16
>>     0000-0000 : PCI CardBus 0000:16
>
> Hi,
>
> Does /proc/iomem show the same thing (i.e., zeros)?

Yes.

> How about if you do the test while logged in as root?

Darn it.  Everything looks normal then in either case.  So the /proc
thing likely is a red herring: something else regarding the io ports is
problematic with loading the thinkpad_ec module.  Sorry for that bit: I
remember the information being valid even for normal users.

I have another computer with a Mate 17.04 distribution that is complete
64bit including userland.  It also masks the ioports like this as
non-root user and does not have the thinkpad_ec loading problem.

So yes: /proc is a red herring.  That already helps.

The kernel versions on both computers are different, but yet I really
suspect that the recent "normalization" of linux-tools (which were
pinned to a non-upgradable amd64 version previously) and binutils to the
32bit versions may be involved.

I may have to install a whole lot of toolchain as amd64 to check for
this angle.  Which is unpretty since it makes the system less
representative for 32bit development.

-- 
David Kastrup