CVE-2026-74733: gpio: pca953x: fix pca953x_irq_bus_sync_unlock regmap lock

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

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

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

gpio: pca953x: fix pca953x_irq_bus_sync_unlock regmap lock

Locking is disabled in the regmap config as this driver uses its own
lock. This means that all calls to regmap functions (read or write) must
hold the i2c_lock. The function pca953x_irq_bus_sync_unlock() did not do
this, and it was therefore possible that multiple threads could cause an
incorrect register to be read/written.

A previous patch partly fixed this, but only protected the write to the
interrupt mask register, and not the read from the direction register.

The Linux kernel CVE team has assigned CVE-2026-74733 to this issue.


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

	Issue introduced in 6.10 with commit bfc6444b57dc7186b6acc964705d7516cbaf3904 and fixed in 7.1.9 with commit e6a2f5f845f50b0c4299bace5111f56d3390a090
	Issue introduced in 6.10 with commit bfc6444b57dc7186b6acc964705d7516cbaf3904 and fixed in 7.2 with commit 9dc325327babe7f159e84cbe9380a45342da0585
	Issue introduced in 6.1.101 with commit 58a5c93bd1a6e949267400080f07e57ffe05ec34
	Issue introduced in 6.6.42 with commit e2ecdddca80dd845df42376e4b0197fe97018ba2
	Issue introduced in 6.9.11 with commit de7cffa53149c7b48bd1bb29b02390c9f05b7f41

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-2026-74733
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/gpio/gpio-pca953x.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/e6a2f5f845f50b0c4299bace5111f56d3390a090
	https://git.kernel.org/stable/c/9dc325327babe7f159e84cbe9380a45342da0585