# CVE-2025-40356: spi: rockchip-sfc: Fix DMA-API usage

> A Linux kernel SPI driver bug causes DMA API warnings and potential instability, requiring a patch to fix improper memory mapping.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Dec 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-40356, DEBIAN-CVE-2025-40356, GHSA-99cm-3rm5-ghgx, ROOT-OS-UBUNTU-2204-CVE-2025-40356, ROOT-OS-UBUNTU-2404-CVE-2025-40356, UBUNTU-CVE-2025-40356

## What is CVE-2025-40356?

CVE-2025-40356 is a high-severity 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:

spi: rockchip-sfc: Fix DMA-API usage

Use DMA-API dma_map_single() call for getting the DMA address of the
transfer buffer instead of hacking with virt_to_phys().

This fixes the following DMA-API debug warning:
------------[ cut here ]------------
DMA-API: rockchip-sfc fe300000.spi: device driver tries to sync DMA memory it has not allocated [device address=0x000000000cf70000] [size=288 bytes]
WARNING: kernel/dma/debug.c:1106 at check_sync+0x1d8/0x690, CPU#2: systemd-udevd/151
Modules linked in: ...
Hardware name: Hardkernel ODROID-M1 (DT)
pstate: 604000c9 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : check_sync+0x1d8/0x690
lr : check_sync+0x1d8/0x690
..
Call trace:
 check_sync+0x1d8/0x690 (P)
 debug_dma_sync_single_for_cpu+0x84/0x8c
 __dma_sync_single_for_cpu+0x88/0x234
 rockchip_sfc_exec_mem_op+0x4a0/0x798 [spi_rockchip_sfc]
 spi_mem_exec_op+0x408/0x498
 spi_nor_read_data+0x170/0x184
 spi_nor_read_sfdp+0x74/0xe4
 spi_nor_parse_sfdp+0x120/0x11f0
 spi_nor_sfdp_init_params_deprecated+0x3c/0x8c
 spi_nor_scan+0x690/0xf88
 spi_nor_probe+0xe4/0x304
 spi_mem_probe+0x6c/0xa8
 spi_probe+0x94/0xd4
 really_probe+0xbc/0x298
 ...

## Which versions are affected by CVE-2025-40356?


## How do I fix CVE-2025-40356?

Apply the vendor's patch.

## Is CVE-2025-40356 being exploited?

There is no known exploitation of CVE-2025-40356 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40356 and fix it if it is affected.

What it is: CVE-2025-40356 is a high-severity 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-2025-40356 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-2025-40356/ (Markdown: https://insights.sbomify.com/CVE-2025-40356/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40356
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40356
- OSV: https://osv.dev/vulnerability/CVE-2025-40356

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40356/
Summaries are generated and may contain mistakes; the official description above is the record.