In the Linux kernel, the following vulnerability has been resolved:

igc: Reinstate IGC_REMOVED logic and implement it properly

The initially merged version of the igc driver code (via commit 146740f9abc4, "igc: Add support for PF") contained the following IGC_REMOVED checks in the igc_rd32/wr32() MMIO accessors:

u32 igc_rd32(struct igc_hw *hw, u32 reg) { u8 __iomem *hw_addr = READ_ONCE(hw->hw_addr); u32 value = 0;

if (IGC_REMOVED(hw_addr)) return ~value;

value = readl(&hw_addr[reg]);

/* reads should not return all F's */ if (!(~value) && (!reg || !(~readl(hw_addr)))) hw->hw_addr = NULL;

return value; }

And:

#define wr32(reg, val) \ do { \ u8 __iomem *hw_addr = READ_ONCE((hw)->hw_addr); \ if (!IGC_REMOVED(hw_addr)) \ writel((val), &hw_addr[(reg)]); \ } while (0)

E.g. igb has similar checks in its MMIO accessors, and has a similar macro E1000_REMOVED, which is implemented as follows:

#define E1000_REMOVED(h) unlikely(!(h))

These checks serve to detect and take note of an 0xffffffff MMIO read return from the device, which can be caused by a PCIe link flap or some other kind of PCI bus error, and to avoid performing MMIO reads and writes from that point onwards.

However, the IGC_REMOVED macro was not originally implemented:

#ifndef IGC_REMOVED #define IGC_REMOVED(a) (0) #endif /* IGC_REMOVED */

This led to the IGC_REMOVED logic to be removed entirely in a subsequent commit (commit 3c215fb18e70, "igc: remove IGC_REMOVED function…

In the Linux kernel, the following vulnerability has been resolved:

igc: Reinstate IGC_REMOVED logic and implement it properly

The initially merged version of the igc driver code (via commit 146740f9abc4, "igc: Add support for PF") contained the following IGC_REMOVED checks in the igc_rd32/wr32() MMIO accessors:

u32 igc_rd32(struct igc_hw *hw, u32 reg) { u8 __iomem *hw_addr = READ_ONCE(hw->hw_addr); u32 value = 0;

if (IGC_REMOVED(hw_addr)) return ~value;

value = readl(&hw_addr[reg]);

/* reads should not return all F's */ if (!(~value) && (!reg || !(~readl(hw_addr)))) hw->hw_addr = NULL;

return value; }

And:

#define wr32(reg, val) \ do { \ u8 __iomem *hw_addr = READ_ONCE((hw)->hw_addr); \ if (!IGC_REMOVED(hw_addr)) \ writel((val), &hw_addr[(reg)]); \ } while (0)

E.g. igb has similar checks in its MMIO accessors, and has a similar macro E1000_REMOVED, which is implemented as follows:

#define E1000_REMOVED(h) unlikely(!(h))

These checks serve to detect and take note of an 0xffffffff MMIO read return from the device, which can be caused by a PCIe link flap or some other kind of PCI bus error, and to avoid performing MMIO reads and writes from that point onwards.

However, the IGC_REMOVED macro was not originally implemented:

#ifndef IGC_REMOVED #define IGC_REMOVED(a) (0) #endif /* IGC_REMOVED */

This led to the IGC_REMOVED logic to be removed entirely in a subsequent commit (commit 3c215fb18e70, "igc: remove IGC_REMOVED function…

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Security update for the Linux Kernel

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.4, Ubuntu:18.04:LTS: linux-azure-5.4, Ubuntu:18.04:LTS: linux-gcp-5.4, Ubuntu:18.04:LTS: linux-hwe-5.4, Ubuntu:18.04:LTS: linux-ibm-5.4, Ubuntu:18.04:LTS: linux-oracle-5.4, Ubuntu:18.04:LTS: linux-raspi-5.4, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3 and 117 more

In the Linux kernel, the following vulnerability has been resolved: igc: Reinstate IGC_REMOVED logic and implement it properly The initially merged version of the igc driver code (via commit 146740f9abc4, "igc: Add support for PF") contained the following IGC_REMOVED checks in the igc_rd32/wr32() MMIO accessors: u32 igc_rd32(struct igc_hw *hw, u32 reg) { u8 __iomem *hw_addr = READ_ONCE(hw->hw_addr); u32 value = 0; if (IGC_REMOVED(hw_addr)) return ~value; value = readl(&hw_addr[reg]); /* reads should not return all F's */ if (!(~value) && (!reg || !(~readl(hw_addr)))) hw->hw_addr = NULL; return value; } And: #define wr32(reg, val) \ do { \ u8 __iomem *hw_addr = READ_ONCE((hw)->hw_addr); \ if (!IGC_REMOVED(hw_addr)) \ writel((val), &hw_addr[(reg)]); \ } while (0) E.g. igb has similar checks in its MMIO accessors, and has a similar macro E1000_REMOVED, which is implemented as follows: #define E1000_REMOVED(h) unlikely(!(h)) These checks serve to detect and take note of an 0xffffffff MMIO read return from the device, which can be caused by a PCIe link flap or some other kind of PCI bus error, and to avoid performing MMIO reads and writes from that point onwards. However, the IGC_REMOVED macro was not originally implemented: #ifndef IGC_REMOVED #define IGC_REMOVED(a) (0) #endif /* IGC_REMOVED */ This led to the IGC_REMOVED logic to be removed entirely in a subsequent commit (commit 3c215fb18e70, "igc: remove IGC_REMOVED function"), with the ra…