CVE-2022-49709: cfi: Fix __cfi_slowpath_diag RCU usage with cpuidle

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-26 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: cfi: Fix __cfi_slowpath_diag RCU usage with cpuidle RCU_NONIDLE usage during __cfi_slowpath_diag can result in an invalid RCU state in the cpuidle code path: WARNING: CPU: 1 PID: 0 at kernel/rcu/tree.c:613 rcu_eqs_enter+0xe4/0x138 ... Call trace: rcu_eqs_enter+0xe4/0x138 rcu_idle_enter+0xa8/0x100 cpuidle_enter_state+0x154/0x3a8 cpuidle_enter+0x3c/0x58 do_idle.llvm.6590768638138871020+0x1f4/0x2ec cpu_startup_entry+0x28/0x2c secondary_start_kernel+0x1b8/0x220 __secondary_switched+0x94/0x98 Instead, call rcu_irq_enter/exit to wake up RCU only when needed and disable interrupts for the entire CFI shadow/module check when we do.

Affected products

Linux kernel: from 5.13 before 5.15.49; from 5.16 before 5.18.6; 5.19-rc1, 5.19-rc2 — fixed in 5.15.49, 5.18.6

How to fix

Upgrade to a fixed version: Linux kernel 5.15.49, 5.18.6. Check the vendor advisory for mitigations.

References

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