Alexandre Ghiti

**Name of the Vulnerable Software and Affected Versions** Linux kernel versions prior to 6.6.74 **Description** A vulnerability has been resolved in the Linux kernel related to PCI/MSI. The issue arises from the lack of irqdomain handling, which triggers a warning on platforms that do not provide PCI/MSI support, such as RISCV. The warning is bogus because the PCI/MSI layer knows whether a PCI/MSI parent domain is associated with the device or not. The problem was exacerbated by weak implementations that return an error, effectively papering over the issue. Loongarch also encountered the same problem by blindly enabling legacy support without implementing the necessary fallbacks. The fix involves correcting the `pci msi domain supports()` function to evaluate the legacy mode and adding a missing supported check into the MSI enable path. **Recommendations** To resolve the issue, update to Linux kernel version 6.6.74 or later. As a temporary workaround, consider disabling the `pci msi setup msi irqs()` function until a patch is available. Restrict access to the vulnerable `pci msi domain supports()` function to minimize the risk of exploitation. Avoid using the `MSI-X` feature in the affected API endpoint until the issue is resolved.

**Name of the Vulnerable Software and Affected Versions** Linux kernel version 6.6.0-rc6ubuntu-defconfig #2 **Description** The issue arises from the failure to check the return value of `find first bit()` before using it as an index array, leading to an array overflow and subsequent panic. This occurs in the `pmu sbi ovf handler()` function. The vulnerability causes a kernel panic due to a fatal exception in interrupt handling. **Recommendations** To resolve this issue, ensure that the return value of `find first bit()` is properly checked before using it as an index array to prevent overflow and panic. As a temporary workaround, consider disabling the `pmu sbi ovf handler()` function until a patch is available. Update to a newer version of the Linux kernel that includes the fix for this vulnerability. At the moment, there is no information about a newer version that contains a fix for this vulnerability.