CVE-2026-45902: power: supply: bq256xx: Fix use-after-free in power_supply_changed()

CVE-2026-45902: power: supply: bq256xx: Fix use-after-free in power_supply_changed()

[Greg Kroah-Hartman]

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

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

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

power: supply: bq256xx: Fix use-after-free in power_supply_changed()

Using the `devm_` variant for requesting IRQ _before_ the `devm_`
variant for allocating/registering the `power_supply` handle, means that
the `power_supply` handle will be deallocated/unregistered _before_ the
interrupt handler (since `devm_` naturally deallocates in reverse
allocation order). This means that during removal, there is a race
condition where an interrupt can fire just _after_ the `power_supply`
handle has been freed, *but* just _before_ the corresponding
unregistration of the IRQ handler has run.

This will lead to the IRQ handler calling `power_supply_changed()` with
a freed `power_supply` handle. Which usually crashes the system or
otherwise silently corrupts the memory...

Note that there is a similar situation which can also happen during
`probe()`; the possibility of an interrupt firing _before_ registering
the `power_supply` handle. This would then lead to the nasty situation
of using the `power_supply` handle *uninitialized* in
`power_supply_changed()`.

Fix this racy use-after-free by making sure the IRQ is requested _after_
the registration of the `power_supply` handle.

The Linux kernel CVE team has assigned CVE-2026-45902 to this issue.


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

	Issue introduced in 5.12 with commit 32e4978bb920d047fe5de3ea42d176f267c01f63 and fixed in 5.15.202 with commit 81d3688c9a2158329391e08f2d0b8ba204216044
	Issue introduced in 5.12 with commit 32e4978bb920d047fe5de3ea42d176f267c01f63 and fixed in 6.1.165 with commit 74b5a88318db97d51bb40f774736553c2acd1514
	Issue introduced in 5.12 with commit 32e4978bb920d047fe5de3ea42d176f267c01f63 and fixed in 6.6.128 with commit cb5c743936edcebc51880eeb6bf04979b5c9438b
	Issue introduced in 5.12 with commit 32e4978bb920d047fe5de3ea42d176f267c01f63 and fixed in 6.12.75 with commit 83c27fdd696ac13d023ef7a0345301be93209c53
	Issue introduced in 5.12 with commit 32e4978bb920d047fe5de3ea42d176f267c01f63 and fixed in 6.18.14 with commit 4b6fb0b6124f558131e502e3ffd03e6583b3ace6
	Issue introduced in 5.12 with commit 32e4978bb920d047fe5de3ea42d176f267c01f63 and fixed in 6.19.4 with commit 8796910131a32ff29275052df768ef022929a394
	Issue introduced in 5.12 with commit 32e4978bb920d047fe5de3ea42d176f267c01f63 and fixed in 7.0 with commit 8005843369723d9c8975b7c4202d1b85d6125302

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-2026-45902
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/power/supply/bq256xx_charger.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/81d3688c9a2158329391e08f2d0b8ba204216044
	https://git.kernel.org/stable/c/74b5a88318db97d51bb40f774736553c2acd1514
	https://git.kernel.org/stable/c/cb5c743936edcebc51880eeb6bf04979b5c9438b
	https://git.kernel.org/stable/c/83c27fdd696ac13d023ef7a0345301be93209c53
	https://git.kernel.org/stable/c/4b6fb0b6124f558131e502e3ffd03e6583b3ace6
	https://git.kernel.org/stable/c/8796910131a32ff29275052df768ef022929a394
	https://git.kernel.org/stable/c/8005843369723d9c8975b7c4202d1b85d6125302