[tip:x86/urgent] x86, pci, mrst: Add extra sanity check in walking the PCI extended cap chain
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From: tip-bot for Jacob Pan on 16 Jul 2010 21:00 Commit-ID: f82c3d71d6fd2e6a3e3416f09099e29087e39abf Gitweb: http://git.kernel.org/tip/f82c3d71d6fd2e6a3e3416f09099e29087e39abf Author: Jacob Pan <jacob.jun.pan(a)linux.intel.com> AuthorDate: Fri, 16 Jul 2010 11:58:26 -0700 Committer: H. Peter Anvin <hpa(a)linux.intel.com> CommitDate: Fri, 16 Jul 2010 16:52:15 -0700 x86, pci, mrst: Add extra sanity check in walking the PCI extended cap chain The fixed bar capability structure is searched in PCI extended configuration space. We need to make sure there is a valid capability ID to begin with otherwise, the search code may stuck in a infinite loop which results in boot hang. This patch adds additional check for cap ID 0, which is also invalid, and indicates end of chain. End of chain is supposed to have all fields zero, but that doesn't seem to always be the case in the field. Suggested-by: "H. Peter Anvin" <hpa(a)zytor.com> Signed-off-by: Jacob Pan <jacob.jun.pan(a)linux.intel.com> Reviewed-by: Jesse Barnes <jbarnes(a)virtuousgeek.org> LKML-Reference: <1279306706-27087-1-git-send-email-jacob.jun.pan(a)linux.intel.com> Signed-off-by: H. Peter Anvin <hpa(a)linux.intel.com> --- arch/x86/pci/mrst.c | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/pci/mrst.c b/arch/x86/pci/mrst.c index 7ef3a27..cb29191 100644 --- a/arch/x86/pci/mrst.c +++ b/arch/x86/pci/mrst.c @@ -66,8 +66,9 @@ static int fixed_bar_cap(struct pci_bus *bus, unsigned int devfn) devfn, pos, 4, &pcie_cap)) return 0; - if (pcie_cap == 0xffffffff) - return 0; + if (PCI_EXT_CAP_ID(pcie_cap) == 0x0000 || + PCI_EXT_CAP_ID(pcie_cap) == 0xffff) + break; if (PCI_EXT_CAP_ID(pcie_cap) == PCI_EXT_CAP_ID_VNDR) { raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number, @@ -76,7 +77,7 @@ static int fixed_bar_cap(struct pci_bus *bus, unsigned int devfn) return pos; } - pos = pcie_cap >> 20; + pos = PCI_EXT_CAP_NEXT(pcie_cap); } return 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |