Date: Wed, 13 Dec 2017 06:55:47 -0800
From: Vadim Lomovtsev <Vadim.Lomovtsev@caviumnetworks.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: robert.moore@intel.com, lv.zheng@intel.com, rafael.j.wysocki@intel.com,
        lenb@kernel.org, linux-acpi@vger.kernel.org, devel@acpica.org,
        linux-kernel@vger.kernel.org, vadim.lomovtsev@cavium.com
Subject: Re: [BUG] acpica: ltp_acpi test case causes kernel crash at
 acpi_ns_walk_namespace
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On Wed, Dec 13, 2017 at 12:45:50AM +0100, Rafael J. Wysocki wrote:
> On Tuesday, December 12, 2017 4:59:19 PM CET Vadim Lomovtsev wrote:
> > Hi guys,
> > 
> > While running LTP tests I've faced kernel crash caused by ltp_acpi test case.
> > I have ACPI support enabled in kernel but kernel is boot with FDT having ACPI
> > disabled. The ltp_acpi test case application is built along with ltp_acpi_cmds
> > module to run ACPI tests.
> > 
> > So my question is - should we update acpica implementation at kernel side by
> > adding 'acpi_disabled' variable checking to the 'acpi_get_devices' function (see
> > patch next to this email, maybe not a good approach) or this should be fixed at LTP
> > side so the ltp_acpi_cmds should be updated in order to check if acpi is enabled
> > before running tests ?
> 
> There should be a check preventing acpi_get_devices() from being called in the
> acpi_disabled case.

In my case I have to update ltp_acpi code then.

> 
> acpi_disabled is Linux-specific and the ACPICA code isn't, so the code calling
> ACPICA functions should check acpi_disabled when necessary.

Agree. However getting back to LTP tests it looks like such calls were implemented
intentionally without checking of aspi_disabled value.

Don't we have any self-testing stuff in acpica to prevent such scenarious ?

WBR,
Vadim

> 
> Thanks,
> Rafael
>