Another way to look at this is that the kernel should not be calling ACPI interfaces if ACPI is disabled.
> -----Original Message----- > From: Vadim Lomovtsev [mailto:vadim.lomovt...@caviumnetworks.com] > Sent: Tuesday, December 12, 2017 7:59 AM > To: Moore, Robert <robert.mo...@intel.com>; Zheng, Lv > <lv.zh...@intel.com>; Wysocki, Rafael J <rafael.j.wyso...@intel.com>; > l...@kernel.org; linux-a...@vger.kernel.org; de...@acpica.org; linux- > ker...@vger.kernel.org > Cc: vadim.lomovt...@cavium.com > Subject: [PATCH] acpi: acpica: add acpi status check prior walking > through namespace > > From: Vadim Lomovtsev <vadim.lomovt...@cavium.com> > > While having kernel built with ACPI support enabled and booted over FDT, > the ltp_acpi test from LTP suite causes kernel crash while calling > acpi_ns_walk_namespace(). The acpi_get_devices is high level wrapper for > it, so we need to protect kernel from crashes by adding acpi status > check before walking through namespace which is not loaded because of > acpi is disabled. > > Signed-off-by: Vadim Lomovtsev <vadim.lomovt...@cavium.com> > --- > drivers/acpi/acpica/nsxfeval.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/acpi/acpica/nsxfeval.c > b/drivers/acpi/acpica/nsxfeval.c index 783f4c8..e0eb9ae 100644 > --- a/drivers/acpi/acpica/nsxfeval.c > +++ b/drivers/acpi/acpica/nsxfeval.c > @@ -52,6 +52,8 @@ > #define _COMPONENT ACPI_NAMESPACE > ACPI_MODULE_NAME("nsxfeval") > > +extern int acpi_disabled; > + > /* Local prototypes */ > static void acpi_ns_resolve_references(struct acpi_evaluate_info > *info); > > @@ -812,6 +814,11 @@ static void acpi_ns_resolve_references(struct > acpi_evaluate_info *info) > > ACPI_FUNCTION_TRACE(acpi_get_devices); > > + /* check if ACPI disabled to prevent kernel crash later */ > + if (acpi_disabled) { > + return_ACPI_STATUS(AE_NOT_CONFIGURED); > + } > + > /* Parameter validation */ > > if (!user_function) { > -- > 1.8.3.1
