In the Linux kernel, the following vulnerability has been resolved:
s390/lcs: Fix return type of lcs_start_xmit()
With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. A proposed warning in clang aims to catch these at compile time, which reveals:
drivers/s390/net/lcs.c:2090:21: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict] .ndo_start_xmit = lcs_start_xmit, ^~~~~~~~~~~~~~ drivers/s390/net/lcs.c:2097:21: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict] .ndo_start_xmit = lcs_start_xmit, ^~~~~~~~~~~~~~
->ndo_start_xmit() in 'struct net_device_ops' expects a return type of 'netdev_tx_t', not 'int'. Adjust the return type of lcs_start_xmit() to match the prototype's to resolve the warning and potential CFI failure, should s390 select ARCH_SUPPORTS_CFI_CLANG in the future.
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade linux | Dec 29, 2025 | Dec 29, 2025 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Dec 24, 2025 |
| Ubuntu | — | Upgrade linux-gcpUpgrade linux-gcp-4.15Upgrade linux-raspi-5.4Upgrade linux-lowlatency-hwe-5.15Upgrade linux-azure-5.4Upgrade linux-intel-iot-realtimeUpgrade linux-hwe-5.4Upgrade linux-awsUpgrade linux-bluefieldUpgrade linux-realtimeUpgrade linux-gcp-fipsUpgrade linux-hweUpgrade linux-intel-iotg-5.15Upgrade linux-azure-4.15Upgrade linux-iotUpgrade linux-gcp-5.4Upgrade linux-gcp-5.15Upgrade linux-azure-fde-5.15Upgrade linux-oracle-5.4Upgrade linux-xilinx-zynqmpUpgrade linux-riscv-5.15Upgrade linux-gkeUpgrade linux-oracle-5.15Upgrade linux-aws-5.4Upgrade linux-raspiUpgrade linux-hwe-5.15Upgrade linux-aws-fipsUpgrade linux-ibm-5.4Upgrade linux-aws-5.15Upgrade linux-gkeopUpgrade linux-azureUpgrade linux-fipsUpgrade linux-nvidiaUpgrade linux-nvidia-tegra-5.15Upgrade linux-kvmUpgrade linuxUpgrade linux-azure-fipsUpgrade linux-azure-5.15Upgrade linux-intel-iotgUpgrade linux-ibmUpgrade linux-lowlatencyUpgrade linux-oracleUpgrade linux-aws-hwe | Jan 6, 2026 | Dec 24, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | May 27, 2026 | Dec 24, 2025 |
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