Commit-ID: 743146db071c4a828159211a295d12ff4f61752f
Gitweb: http://git.kernel.org/tip/743146db071c4a828159211a295d12ff4f61752f
Author: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
AuthorDate: Tue, 15 Mar 2016 09:20:33 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
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 <vkuznets@xxxxxxxxxx>
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Bjorn Helgaas <helgaas@xxxxxxxxxx>
Cc: Cathy Avery <cavery@xxxxxxxxxx>
Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1458030033-10122-1-git-send-email-vkuznets@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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;
--
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