# CVE-2025-68202: sched_ext: Fix unsafe locking in the scx_dump_state()

> A race condition in the Linux kernel scheduler can cause a deadlock and system crash when running with PREEMPT_RT enabled.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-68202, DEBIAN-CVE-2025-68202, GHSA-9mh6-8446-rm89, ROOT-OS-DEBIAN-13-CVE-2025-68202, UBUNTU-CVE-2025-68202

## What is CVE-2025-68202?

CVE-2025-68202 is a vulnerability in Linux, published on 16 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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().

## Which versions are affected by CVE-2025-68202?


## How do I fix CVE-2025-68202?

Apply the vendor's patch.

## Is CVE-2025-68202 being exploited?

There is no known exploitation of CVE-2025-68202 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68202 and fix it if it is affected.

What it is: CVE-2025-68202 is a vulnerability in Linux, published on 16 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-68202 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-68202/ (Markdown: https://insights.sbomify.com/CVE-2025-68202/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68202
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68202
- OSV: https://osv.dev/vulnerability/CVE-2025-68202

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68202/
Summaries are generated and may contain mistakes; the official description above is the record.