CVE-2026-64499: iio: adc: ti-ads1119: fix PM reference leak in buffer preenable

From: Greg Kroah-Hartman <[email protected]>

Description
===========

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

iio: adc: ti-ads1119: fix PM reference leak in buffer preenable

ads1119_triggered_buffer_preenable() resumes the device with
pm_runtime_resume_and_get() before starting a conversion.

If i2c_smbus_write_byte() fails, the function returns the error directly
and leaves the runtime PM usage counter elevated. The matching
postdisable callback is not called when preenable fails, so the reference
is leaked and the device may remain runtime-active indefinitely.

Store the I2C transfer result in ret and drop the runtime PM reference on
failure before returning the error.

The Linux kernel CVE team has assigned CVE-2026-64499 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.11 with commit a9306887eba41c5fe7232727a8147da3d3c4f83c and fixed in 6.12.96 with commit f40292fb19399a3c3f82de698023ba87c01e66cf
	Issue introduced in 6.11 with commit a9306887eba41c5fe7232727a8147da3d3c4f83c and fixed in 6.18.39 with commit ffb2195921c3d629194b9807de589578df9f9cb8
	Issue introduced in 6.11 with commit a9306887eba41c5fe7232727a8147da3d3c4f83c and fixed in 7.1.4 with commit 6537f08100189d12bec4975000244e6ac4873c28
	Issue introduced in 6.11 with commit a9306887eba41c5fe7232727a8147da3d3c4f83c and fixed in 7.2-rc3 with commit adf4bc07f814da8329278d32600147f5a150938c

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-64499
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/iio/adc/ti-ads1119.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/f40292fb19399a3c3f82de698023ba87c01e66cf
	https://git.kernel.org/stable/c/ffb2195921c3d629194b9807de589578df9f9cb8
	https://git.kernel.org/stable/c/6537f08100189d12bec4975000244e6ac4873c28
	https://git.kernel.org/stable/c/adf4bc07f814da8329278d32600147f5a150938c