In the Linux kernel, the following vulnerability has been resolved:
ext4: Fix function prototype mismatch for ext4_feat_ktype
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.
ext4_feat_ktype was setting the "release" handler to "kfree", which doesn't have a matching function prototype. Add a simple wrapper with the correct prototype.
This was found as a result of Clang's new -Wcast-function-type-strict flag, which is more sensitive than the simpler -Wcast-function-type, which only checks for type width mismatches.
Note that this code is only reached when ext4 is a loadable module and it is being unloaded:
CFI failure at kobject_put+0xbb/0x1b0 (target: kfree+0x0/0x180; expected type: 0x7c4aa698) ... RIP: 0010:kobject_put+0xbb/0x1b0 ... Call Trace: <TASK> ext4_exit_sysfs+0x14/0x60 [ext4] cleanup_module+0x67/0xedb [ext4]
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade python-perfUpgrade kernel-debuginfo-common-aarch64Upgrade perfUpgrade kernel-tools-debuginfoUpgrade kernel-debuginfoUpgrade bpftool-debuginfoUpgrade perf-debuginfoUpgrade kernel-headersUpgrade kernel-livepatch-5.15.102-61.139Upgrade python-perf-debuginfoUpgrade kernelUpgrade kernel-tools-develUpgrade kernel-livepatch-5.10.173-154.642Upgrade bpftoolUpgrade kernel-toolsUpgrade kernel-develUpgrade kernel-debuginfo-common-x86_64 | May 20, 2026 | May 20, 2026 |
| Amazon_linux_2023 | — | Upgrade perf-debuginfoUpgrade kernel-debuginfo-common-aarch64Upgrade python3-perfUpgrade perfUpgrade kernel-tools-develUpgrade kernel-develUpgrade kernel-headersUpgrade kernel-debuginfoUpgrade kernel-toolsUpgrade kernel-debuginfo-common-x86_64Upgrade bpftool-debuginfoUpgrade kernel-livepatch-6.1.15-28.43Upgrade kernel-tools-debuginfoUpgrade kernel-libbpf-develUpgrade kernelUpgrade kernel-libbpfUpgrade kernel-libbpf-staticUpgrade bpftoolUpgrade python3-perf-debuginfo | Sep 30, 2025 | Sep 15, 2025 |
| Debian | — | Upgrade linux | Sep 17, 2025 | Sep 17, 2025 |
| Redhat_linux | — | No solution existsUpgrade kernel | Nov 14, 2025 | Sep 15, 2025 |
| Ubuntu | — | Upgrade linux-gcp-5.15Upgrade linux-gkeUpgrade linux-realtimeUpgrade linux-nvidia-tegra-5.15Upgrade linux-xilinx-zynqmpUpgrade linux-azureUpgrade linux-fipsUpgrade linuxUpgrade linux-azure-fipsUpgrade linux-oracle-5.4Upgrade linux-riscv-5.15Upgrade linux-lowlatency-hwe-5.15Upgrade linux-aws-5.15Upgrade linux-azure-fdeUpgrade linux-hwe-5.15Upgrade linux-raspiUpgrade linux-gkeopUpgrade linux-oracleUpgrade linux-aws-5.4Upgrade linux-oracle-5.15Upgrade linux-lowlatencyUpgrade linux-nvidiaUpgrade linux-intel-iotgUpgrade linux-raspi-5.4Upgrade linux-azure-5.15Upgrade linux-ibm-5.4Upgrade linux-iotUpgrade linux-ibmUpgrade linux-intel-iotg-5.15Upgrade linux-hwe-5.4Upgrade linux-gcpUpgrade linux-kvmUpgrade linux-intel-iot-realtimeUpgrade linux-gcp-5.4Upgrade linux-azure-5.4Upgrade linux-awsUpgrade linux-bluefieldUpgrade linux-gcp-fipsUpgrade linux-aws-fips | Sep 19, 2025 | Sep 16, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Oct 15, 2025 | Sep 15, 2025 |
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