Commit-ID: 743146db071c4a828159211a295d12ff4f61752f Gitweb: http://git.kernel.org/tip/743146db071c4a828159211a295d12ff4f61752f Author: Vitaly Kuznetsov <vkuzn...@redhat.com> AuthorDate: Tue, 15 Mar 2016 09:20:33 +0100 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 15 Mar 2016 11:08:26 +0100
x86/video: Don't assume all FB devices are PCI devices 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 ... [<ffffffff81581308>] dump_stack+0x63/0x8b [<ffffffff812e1f99>] print_trailer+0xf9/0x150 [<ffffffff812e7344>] object_err+0x34/0x40 [<ffffffff812e9630>] kasan_report_error+0x230/0x550 [<ffffffff812e9ee8>] kasan_report+0x58/0x60 [<ffffffff812e4500>] ? ___slab_alloc+0x80/0x490 [<ffffffff81878a28>] ? fb_is_primary_device+0x58/0x70 [<ffffffff812e87cd>] __asan_load8+0x5d/0x70 [<ffffffff81878a28>] fb_is_primary_device+0x58/0x70 [<ffffffff8162357a>] register_framebuffer+0xda/0x5b0 [<ffffffff816234a0>] ? 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. While on it, clean up the function. Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> Acked-by: Bjorn Helgaas <bhelg...@google.com> Cc: Bjorn Helgaas <helg...@kernel.org> Cc: Cathy Avery <cav...@redhat.com> Cc: K. Y. Srinivasan <k...@microsoft.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/1458030033-10122-1-git-send-email-vkuzn...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/video/fbdev.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c index d5644bb..9fd2484 100644 --- a/arch/x86/video/fbdev.c +++ b/arch/x86/video/fbdev.c @@ -14,26 +14,24 @@ int fb_is_primary_device(struct fb_info *info) { struct device *device = info->device; - struct pci_dev *pci_dev = NULL; struct pci_dev *default_device = vga_default_device(); - struct resource *res = NULL; + struct pci_dev *pci_dev; + struct resource *res; - 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; - else - return 0; + return 0; } - res = &pci_dev->resource[PCI_ROM_RESOURCE]; + res = pci_dev->resource + PCI_ROM_RESOURCE; - if (res && res->flags & IORESOURCE_ROM_SHADOW) + if (res->flags & IORESOURCE_ROM_SHADOW) return 1; return 0;
