CVE-2025-68202

Unknown Unknown - Not Provided

BaseFortify

Publication date: 2025-12-16

Last updated on: 2025-12-18

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix unsafe locking in the scx_dump_state() For built with CONFIG_PREEMPT_RT=y kernels, the dump_lock will be converted sleepable spinlock and not disable-irq, so the following scenarios occur: inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. irq_work/0/27 [HC0[0]:SC0[0]:HE1:SE1] takes: (&rq->__lock){?...}-{2:2}, at: raw_spin_rq_lock_nested+0x2b/0x40 {IN-HARDIRQ-W} state was registered at: lock_acquire+0x1e1/0x510 _raw_spin_lock_nested+0x42/0x80 raw_spin_rq_lock_nested+0x2b/0x40 sched_tick+0xae/0x7b0 update_process_times+0x14c/0x1b0 tick_periodic+0x62/0x1f0 tick_handle_periodic+0x48/0xf0 timer_interrupt+0x55/0x80 __handle_irq_event_percpu+0x20a/0x5c0 handle_irq_event_percpu+0x18/0xc0 handle_irq_event+0xb5/0x150 handle_level_irq+0x220/0x460 __common_interrupt+0xa2/0x1e0 common_interrupt+0xb0/0xd0 asm_common_interrupt+0x2b/0x40 _raw_spin_unlock_irqrestore+0x45/0x80 __setup_irq+0xc34/0x1a30 request_threaded_irq+0x214/0x2f0 hpet_time_init+0x3e/0x60 x86_late_time_init+0x5b/0xb0 start_kernel+0x308/0x410 x86_64_start_reservations+0x1c/0x30 x86_64_start_kernel+0x96/0xa0 common_startup_64+0x13e/0x148 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&rq->__lock); <Interrupt> lock(&rq->__lock); *** DEADLOCK *** stack backtrace: CPU: 0 UID: 0 PID: 27 Comm: irq_work/0 Call Trace: <TASK> dump_stack_lvl+0x8c/0xd0 dump_stack+0x14/0x20 print_usage_bug+0x42e/0x690 mark_lock.part.44+0x867/0xa70 ? __pfx_mark_lock.part.44+0x10/0x10 ? string_nocheck+0x19c/0x310 ? number+0x739/0x9f0 ? __pfx_string_nocheck+0x10/0x10 ? __pfx_check_pointer+0x10/0x10 ? kvm_sched_clock_read+0x15/0x30 ? sched_clock_noinstr+0xd/0x20 ? local_clock_noinstr+0x1c/0xe0 __lock_acquire+0xc4b/0x62b0 ? __pfx_format_decode+0x10/0x10 ? __pfx_string+0x10/0x10 ? __pfx___lock_acquire+0x10/0x10 ? __pfx_vsnprintf+0x10/0x10 lock_acquire+0x1e1/0x510 ? raw_spin_rq_lock_nested+0x2b/0x40 ? __pfx_lock_acquire+0x10/0x10 ? dump_line+0x12e/0x270 ? raw_spin_rq_lock_nested+0x20/0x40 _raw_spin_lock_nested+0x42/0x80 ? raw_spin_rq_lock_nested+0x2b/0x40 raw_spin_rq_lock_nested+0x2b/0x40 scx_dump_state+0x3b3/0x1270 ? finish_task_switch+0x27e/0x840 scx_ops_error_irq_workfn+0x67/0x80 irq_work_single+0x113/0x260 irq_work_run_list.part.3+0x44/0x70 run_irq_workd+0x6b/0x90 ? __pfx_run_irq_workd+0x10/0x10 smpboot_thread_fn+0x529/0x870 ? __pfx_smpboot_thread_fn+0x10/0x10 kthread+0x305/0x3f0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x40/0x70 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> This commit therefore use rq_lock_irqsave/irqrestore() to replace rq_lock/unlock() in the scx_dump_state().

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2025-12-16

Last Modified

2025-12-18

Generated

2026-07-27

AI Q&A

2025-12-16

EPSS Evaluated

2026-07-25

NVD

CVE-2025-68202

EUVD

EUVD-2025-203694

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability is an unsafe locking issue in the Linux kernel's sched_ext component, specifically in the scx_dump_state() function. When the kernel is built with CONFIG_PREEMPT_RT=y, the dump_lock is converted to a sleepable spinlock that does not disable interrupts, leading to inconsistent locking states and a potential deadlock scenario. This occurs because the same lock (&rq->__lock) can be acquired twice in an interrupt context, causing a deadlock. The fix replaces the locking mechanism with irqsave/irqrestore variants to prevent this unsafe locking.

Detection Guidance

This vulnerability relates to unsafe locking in the Linux kernel's sched_ext component, specifically in scx_dump_state() when CONFIG_PREEMPT_RT=y is enabled. Detection would involve monitoring for kernel deadlocks or lock inconsistencies related to raw_spinlocks and irq_work threads. You can check kernel logs (e.g., using 'dmesg' or 'journalctl -k') for stack traces or deadlock messages similar to those described in the vulnerability. Commands to help detect issues include: 'dmesg | grep -i deadlock', 'journalctl -k | grep -i irq_work', and monitoring for kernel warnings or errors related to spinlocks or irq_work threads. Additionally, tools like 'perf' or kernel debugging tools may help trace locking issues, but no specific commands are provided in the context.

Impact Analysis

This vulnerability can cause a deadlock in the Linux kernel when running with real-time preemption (CONFIG_PREEMPT_RT=y). A deadlock can halt or severely disrupt system operations, potentially causing system freezes or crashes, which impacts system reliability and availability.

Mitigation Strategies

The vulnerability is fixed by replacing rq_lock/unlock() with rq_lock_irqsave/irqrestore() in the scx_dump_state() function. To mitigate this vulnerability, you should update your Linux kernel to a version that includes this fix, ensuring that the unsafe locking scenario is resolved.

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