---
id: CVE-2026-98826
title: 'rtc: ac100: Fix clock provider use-after-free on probe failure'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  rtc: ac100: Fix clock provider use-after-free on probe failure

  ac100_rtc_register_clks() registers the RTC-32k clock with
  clk_hw_register_fixed_rate() and the clock pr…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= d00a18a42c1483924de086ddfb0efe8da1dba3ac <
    12bcd20d76703ee2baf52224d287b7fea096b12f
  - >-
    Linux >= d00a18a42c1483924de086ddfb0efe8da1dba3ac <
    9cff19ddd7f90c1f572a0f83cfc41de8f8dcbcd8
  - >-
    Linux >= d00a18a42c1483924de086ddfb0efe8da1dba3ac <
    55ca60ba336632349f7c4585d22ba74ae355b7ce
  - >-
    Linux >= d00a18a42c1483924de086ddfb0efe8da1dba3ac <
    fcf0b58e976e83adf246b014518e49c662b96f5e
  - Linux 4.9
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:49:19.709Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98826'
references:
  - url: 'https://git.kernel.org/stable/c/12bcd20d76703ee2baf52224d287b7fea096b12f'
  - url: 'https://git.kernel.org/stable/c/9cff19ddd7f90c1f572a0f83cfc41de8f8dcbcd8'
  - url: 'https://git.kernel.org/stable/c/55ca60ba336632349f7c4585d22ba74ae355b7ce'
  - url: 'https://git.kernel.org/stable/c/fcf0b58e976e83adf246b014518e49c662b96f5e'
tags:
  - cve.org
ingestedAt: '2026-10-18T16:47:32.472Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

rtc: ac100: Fix clock provider use-after-free on probe failure

ac100_rtc_register_clks() registers the RTC-32k clock with
clk_hw_register_fixed_rate() and the clock provider with
of_clk_add_hw_provider(). Neither is device managed, and both are
released only from ac100_rtc_remove(). The driver core does not call
remove() when probe() fails: really_probe() reaches probe_failed below
the device_remove() call and goes straight to releasing the device's
managed resources.

ac100_rtc_probe() ends with

	return devm_rtc_register_device(chip->rtc);

so if that fails after the clocks have been registered, the provider is
left on the global of_clk_providers list holding chip->clk_data, which
was allocated with devm_kzalloc() and is freed while probe() unwinds. A
later lookup on this device tree node then reads freed memory in
of_clk_hw_onecell_get(). Consumers that do exactly that exist in tree:
the wifi power sequence nodes on sun8i-a83t-bananapi-m3 and
sun8i-a83t-cubietruck-plus take <&ac100_rtc 1>, and the sun9i-a80 boards
route osc32k through <&ac100_rtc 0>. The window is narrow, as
devm_rtc_register_device() can only fail with -ENOMEM here, but the
provider is left dangling whenever it does.

The RTC-32k clock is leaked on the same path. Since clk_core_lookup()
searches a global list that is not scoped per device, __clk_register()
rejects the duplicate name with -EEXIST, so the leak also makes a later
probe of the same device fail.

The error path that returns -EINVAL when the ADDA 4M parent clock cannot
be found leaks the RTC-32k clock in the same way. No provider has been
registered at that point, so that one is a leak rather than a
use-after-free.

Register both with devm_clk_hw_register_fixed_rate() and
devm_of_clk_add_hw_provider() so that they are released whenever the
device goes away, on a failed probe as well as on unbind. Devres
releases in reverse order of acquisition, so the provider is removed
before chip->clk_data is freed, and the clkout children are now
unregistered before their parent rather than after it.
ac100_rtc_unregister_clks() and the remove callback then have nothing
left to do and are removed.

## Affected

- `Linux >= d00a18a42c1483924de086ddfb0efe8da1dba3ac < 12bcd20d76703ee2baf52224d287b7fea096b12f`
- `Linux >= d00a18a42c1483924de086ddfb0efe8da1dba3ac < 9cff19ddd7f90c1f572a0f83cfc41de8f8dcbcd8`
- `Linux >= d00a18a42c1483924de086ddfb0efe8da1dba3ac < 55ca60ba336632349f7c4585d22ba74ae355b7ce`
- `Linux >= d00a18a42c1483924de086ddfb0efe8da1dba3ac < fcf0b58e976e83adf246b014518e49c662b96f5e`
- `Linux 4.9`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.