CVE-2025-71119 — powerpc/kexec: Enable SMT before waking offline CPUs

Affected: Linux

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

powerpc/kexec: Enable SMT before waking offline CPUs

If SMT is disabled or a partial SMT state is enabled, when a new kernel image is loaded for kexec, on reboot the following warning is observed:

kexec: Waking offline cpu 228. WARNING: CPU: 0 PID: 9062 at arch/powerpc/kexec/core_64.c:223 kexec_prepare_cpus+0x1b0/0x1bc [snip] NIP kexec_prepare_cpus+0x1b0/0x1bc LR kexec_prepare_cpus+0x1a0/0x1bc Call Trace: kexec_prepare_cpus+0x1a0/0x1bc (unreliable) default_machine_kexec+0x160/0x19c machine_kexec+0x80/0x88 kernel_kexec+0xd0/0x118 __do_sys_reboot+0x210/0x2c4 system_call_exception+0x124/0x320 system_call_vectored_common+0x15c/0x2ec

This occurs as add_cpu() fails due to cpu_bootable() returning false for CPUs that fail the cpu_smt_thread_allowed() check or non primary threads if SMT is disabled.

Fix the issue by enabling SMT and resetting the number of SMT threads to the number of threads per core, before attempting to wake up all present CPUs.

USN-8177-1 — linux, linux-realtime vulnerabilities

Affected: Ubuntu:25.10: linux, Ubuntu:25.10: linux-realtime

Josh Eads, Kristoffer Janke, Eduardo Vela Nava, Tavis Ormandy, and Matteo Rizzo discovered that some AMD Zen processors did not properly verify the signature of CPU microcode. This flaw is known as EntrySign. A privileged attacker could possibly use this issue to cause load malicious CPU microcode causing loss of integrity and confidentiality. (CVE-2024-36347)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - MIPS architecture; - PowerPC architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Cryptographic API; - ACPI drivers; - Ublk userspace block driver; - Bluetooth drivers; - Character device driver; - TPM device driver; - Clock framework and drivers; - GPU drivers; - Hardware monitoring drivers; - Intel Trace Hub HW tracing drivers; - InfiniBand drivers; - Input Device core drivers; - Input Device (Mouse) drivers; - IOMMU subsystem; - Multiple devices driver; - Media drivers; - Network drivers; - Mellanox network drivers; - STMicroelectronics network drivers; - Ethernet team driver; - PA-RISC drivers; - Chrome hardware platform drivers; - x86 platform drivers; - SCSI subsystem; - SPI subsystem; - TCM subsystem; - Freescale USB OTG Transceiver Driver; - USB Type-C Connector System Software Interface driver; - Watchdog drivers; - BTRFS file sy…

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CVE-2025-71119 — powerpc/kexec: Enable SMT before waking offline CPUs

USN-8177-1 — linux, linux-realtime vulnerabilities