CVE-2026-90249: iio: light: gp2ap002: Fix unbalanced runtime PM on repeated event writes

CVE-2026-90249: iio: light: gp2ap002: Fix unbalanced runtime PM on repeated event writes

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

iio: light: gp2ap002: Fix unbalanced runtime PM on repeated event writes

The IIO core does not filter duplicate writes to the event enable
attribute, so writing the same value twice invokes
write_event_config() twice. Enabling twice leaks a runtime PM
reference, preventing the device from ever suspending again;
disabling twice underflows the usage count and triggers a
"Runtime PM usage count underflow" warning.

Bail out early when the requested state matches the current state.
While at it, switch to pm_runtime_resume_and_get() so a failed
resume is propagated to userspace instead of silently marking the
event enabled.

The Linux kernel CVE team has assigned CVE-2026-90249 to this issue.


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

	Issue introduced in 5.7 with commit 97d642e23037c5545266f9564c9b81e6db81b122 and fixed in 5.10.270 with commit b2d7a97d75b648a643f60d77f4d6d70161268855
	Issue introduced in 5.7 with commit 97d642e23037c5545266f9564c9b81e6db81b122 and fixed in 5.15.221 with commit 685d9d1e5c47e024413981fb7eddab86132b04a1
	Issue introduced in 5.7 with commit 97d642e23037c5545266f9564c9b81e6db81b122 and fixed in 6.1.188 with commit 56fe8e5f313a64e458bb6f8b982de925345e21a7
	Issue introduced in 5.7 with commit 97d642e23037c5545266f9564c9b81e6db81b122 and fixed in 6.6.157 with commit 8e76ab81319858736ccf23141e9415f9a1869337
	Issue introduced in 5.7 with commit 97d642e23037c5545266f9564c9b81e6db81b122 and fixed in 6.12.110 with commit 70b9482926ca92862460e659f5e5fde99ae0b4fa
	Issue introduced in 5.7 with commit 97d642e23037c5545266f9564c9b81e6db81b122 and fixed in 6.18.52 with commit 0fc740c25c9abb25113398ebb58e2f2ce57741a7
	Issue introduced in 5.7 with commit 97d642e23037c5545266f9564c9b81e6db81b122 and fixed in 7.2.6 with commit 470edb012b1d9a4fba1cd59e329e60f0798c791a
	Issue introduced in 5.7 with commit 97d642e23037c5545266f9564c9b81e6db81b122 and fixed in 7.3-rc1 with commit 579c049b4cb6fc72ce2c505fc5334540be0efcd3

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-2026-90249
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/light/gp2ap002.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/b2d7a97d75b648a643f60d77f4d6d70161268855
	https://git.kernel.org/stable/c/685d9d1e5c47e024413981fb7eddab86132b04a1
	https://git.kernel.org/stable/c/56fe8e5f313a64e458bb6f8b982de925345e21a7
	https://git.kernel.org/stable/c/8e76ab81319858736ccf23141e9415f9a1869337
	https://git.kernel.org/stable/c/70b9482926ca92862460e659f5e5fde99ae0b4fa
	https://git.kernel.org/stable/c/0fc740c25c9abb25113398ebb58e2f2ce57741a7
	https://git.kernel.org/stable/c/470edb012b1d9a4fba1cd59e329e60f0798c791a
	https://git.kernel.org/stable/c/579c049b4cb6fc72ce2c505fc5334540be0efcd3