HIGH Introduced in 6.0
vfio_ccw NotOper Lock
CVE-2026-80549
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
KernelScan AI4.4MEDIUM
01Description
In the Linux kernel, the following vulnerability has been resolved: s390/vfio_ccw: Move cp cleanup out of not operational The fsm_notoper() routine is called when the device has been lost, and is (by definition) no longer operational. Since this can happen asynchronously from the normal behavior of the driver, the cleanup may happen when holding other locks in the calling sequence (notably, the cio subchannel lock). Push the cleanup of the private->cp resources to a workqueue, where it can be done out from under that lock sequence and a future patch can safely manage the locking requirements.
02KernelScan AI Analysis
Risk summary
A locking defect in the s390 vfio-ccw driver can cause a kernel deadlock or crash when a channel device transitions to the not-operational state asynchronously. The issue is reachable on s390 hosts that mediate channel I/O devices to guests via VFIO. A local user or process with access to the mediated device path can reach the vulnerable code.
Vulnerability analysis
When a mediated channel-I/O device on s390 becomes not-operational, the driver frees active channel-program resources while holding internal locks from the I/O stack, which can deadlock or crash the kernel. The fix defers that cleanup so it runs outside the affected lock sequence, and waits for it to finish during device shutdown. The issue only affects s390 systems that use VFIO to mediate channel devices, and is reachable when the underlying device is lost while active.
Lifecycle
03Fix Versions
| Branch | Introduced | Fixed in | Patch commit |
|---|---|---|---|
| 6.12 | 6.0 | 6.12.105 | 4e3301e2a651 |
| 6.18 | 6.0 | 6.18.46 | af1759d8e6e6 |
| mainline | 6.0 | 7.2 | 0c11f61a876e |
| 6.1 | 6.0 | 6.1.185 | c9b85aa2cf73 |
| 6.6 | 6.0 | 6.6.153 | f98a9890ca42 |
| 7.1 | 6.0 | 7.1.10 | 56100baa0eb7 |
| cip/6.1 | 6.0 | 6.1.187-cip60 | c9b85aa2cf73 |
| cip/6.12 | 6.0 | 6.12.108-cip31 | 4e3301e2a651 |