From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965335AbcCNOnK (ORCPT ); Mon, 14 Mar 2016 10:43:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55380 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965201AbcCNOnI (ORCPT ); Mon, 14 Mar 2016 10:43:08 -0400 From: Vitaly Kuznetsov To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Cathy Avery , "K. Y. Srinivasan" , Bjorn Helgaas Subject: [PATCH v2] x86: don't assume all fb devices are PCI devices Date: Mon, 14 Mar 2016 15:42:57 +0100 Message-Id: <1457966577-4006-1-git-send-email-vkuznets@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When booting Hyper-V Generation 2 guests KASAN reports the following out-of-bounds access: BUG: KASAN: slab-out-of-bounds in fb_is_primary_device+0x58/0x70 at addr ffff880079cf0eb0 Read of size 8 by task swapper/0/1 ... [] dump_stack+0x63/0x8b [] print_trailer+0xf9/0x150 [] object_err+0x34/0x40 [] kasan_report_error+0x230/0x550 [] kasan_report+0x58/0x60 [] ? ___slab_alloc+0x80/0x490 [] ? fb_is_primary_device+0x58/0x70 [] __asan_load8+0x5d/0x70 [] fb_is_primary_device+0x58/0x70 [] register_framebuffer+0xda/0x5b0 [] ? remove_conflicting_framebuffers+0x50/0x50 ... The issue is caused by the to_pci_dev() call with no check that the given info->device is in fact a pci device and some fb devices (Hyper-V FB, EFI FB,...) are not. Signed-off-by: Vitaly Kuznetsov --- Changes since v1: use dev_is_pci() instead of full scan [Bjorn Helgaas]. --- arch/x86/video/fbdev.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c index d5644bb..9f2fe63 100644 --- a/arch/x86/video/fbdev.c +++ b/arch/x86/video/fbdev.c @@ -18,12 +18,11 @@ int fb_is_primary_device(struct fb_info *info) struct pci_dev *default_device = vga_default_device(); struct resource *res = NULL; - if (device) - pci_dev = to_pci_dev(device); - - if (!pci_dev) + if (!device || !dev_is_pci(device)) return 0; + pci_dev = to_pci_dev(device); + if (default_device) { if (pci_dev == default_device) return 1; -- 2.5.0