# CVE-2026-45981: s390/cio: Fix device lifecycle handling in css\_alloc\_subchannel()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-27 · Updated: 2026-06-01

## Affected

- Linux: version range not reported
- Linux: 3.10

## Description

In the Linux kernel, the following vulnerability has been resolved: s390/cio: Fix device lifecycle handling in css_alloc_subchannel() `css_alloc_subchannel()` calls `device_initialize()` before setting up the DMA masks. If `dma_set_coherent_mask()` or `dma_set_mask()` fails, the error path frees the subchannel structure directly, bypassing the device model reference counting. Once `device_initialize()` has been called, the embedded struct device must be released via `put_device()`, allowing the release callback to free the container structure. Fix the error path by dropping the initial device reference with `put_device()` instead of calling `kfree()` directly. This ensures correct device lifetime handling and avoids potential use-after-free or double-free issues.

## 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.
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## 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/abb6e07f46a740cda4f07d1b561ae4eaa7a1df42
- https://git.kernel.org/stable/c/f96c5ccf95ae5f27218c1ce2d6a3ad2d3e105424
- https://git.kernel.org/stable/c/6715560527e343a387e4a0d2e6c401748e89fa55
- https://git.kernel.org/stable/c/c35cfbb5341ba05ad1b4476ffc3c21cc3ff8f603
- https://git.kernel.org/stable/c/f65c75b0b9b5a390bc3beadcde0a6fbc3ad118f7

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Page: https://cve.now/CVE-2026-45981
JSON: https://cve.now/api/v1/entries/CVE-2026-45981
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