From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiang Liu Subject: [Bugfix 2/2] x86/PCI/ACPI: Relax ACPI resource descriptor checks to work around BIOS bugs Date: Wed, 4 Mar 2015 16:47:12 +0800 Message-ID: <1425458832-28777-2-git-send-email-jiang.liu@linux.intel.com> References: <1425458832-28777-1-git-send-email-jiang.liu@linux.intel.com> Return-path: In-Reply-To: <1425458832-28777-1-git-send-email-jiang.liu@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J . Wysocki" , Thomas Voegtle , Hudd , Prakash Punnoor , Francois Romieu , Dave Airlie , Marcel Holtmann , Len Brown Cc: Jiang Liu , Bjorn Helgaas , LKML , linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, Thomas Gleixner , Lv Zheng List-Id: linux-acpi@vger.kernel.org Some BIOSes report incorrect length for ACPI address space descriptors, so relax the checks to avoid regressions. This issue has appeared several times as: 3162b6f0c5e1 ("PNPACPI: truncate _CRS windows with _LEN > _MAX - _MIN + 1") d558b483d5a7 ("x86/PCI: truncate _CRS windows with _LEN > _MAX - _MIN + 1") f238b414a74a ("PNPACPI: compute Address Space length rather than using _LEN") 48728e077480 ("x86/PCI: compute Address Space length rather than using _LEN") Please refer to https://bugzilla.kernel.org/show_bug.cgi?id=94221 for more details and example malformed ACPI resource descriptors. Signed-off-by: Jiang Liu Tested-by: Dave Airlie Tested-by: Prakash Punnoor --- drivers/acpi/resource.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c index c723668e3e27..5589a6e2a023 100644 --- a/drivers/acpi/resource.c +++ b/drivers/acpi/resource.c @@ -42,8 +42,10 @@ static bool acpi_dev_resource_len_valid(u64 start, u64 end, u64 len, bool io) * CHECKME: len might be required to check versus a minimum * length as well. 1 for io is fine, but for memory it does * not make any sense at all. + * Note: some BIOSes report incorrect length for ACPI address space + * descriptor, so remove check of 'reslen == len' to avoid regression. */ - if (len && reslen && reslen == len && start <= end) + if (len && reslen && start <= end) return true; pr_debug("ACPI: invalid or unassigned resource %s [%016llx - %016llx] length [%016llx]\n", -- 1.7.10.4