CVE-2026-90367: wifi: mt76: mt7996: hold dev->mt76.mutex while disabling tx worker in SER

CVE-2026-90367: wifi: mt76: mt7996: hold dev->mt76.mutex while disabling tx worker in SER

[Greg Kroah-Hartman]

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

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

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

wifi: mt76: mt7996: hold dev->mt76.mutex while disabling tx worker in SER

mt7996_mac_reset_work() parked the tx worker and disabled the RX/TX NAPIs
before taking dev->mt76.mutex. mt76_worker_disable()/_enable() are plain
kthread park/unpark, not refcounted, and __mt76_set_channel() toggles the
same worker and the MT76_RESET bit under the mutex. An L1 SER racing a
channel switch could therefore have the worker unparked and MT76_RESET
cleared while the reset path resets the DMA rings, corrupting descriptors
or tokens. Take the mutex before disabling the worker, as mt7915 does.

The Linux kernel CVE team has assigned CVE-2026-90367 to this issue.


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

	Issue introduced in 6.4 with commit 27015b6fbcca836c6dbf196afc266e068af4aeec and fixed in 6.18.52 with commit 906ad486ba5c4933d82e1ebe0685656390a48450
	Issue introduced in 6.4 with commit 27015b6fbcca836c6dbf196afc266e068af4aeec and fixed in 7.2.6 with commit 594c4b7f89f9ea75dc9c50b5e4c4296db4a3d701
	Issue introduced in 6.4 with commit 27015b6fbcca836c6dbf196afc266e068af4aeec and fixed in 7.3-rc1 with commit 6190db312b8230813f529f014b26247c6d9800d0

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-2026-90367
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/net/wireless/mediatek/mt76/mt7996/mac.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/906ad486ba5c4933d82e1ebe0685656390a48450
	https://git.kernel.org/stable/c/594c4b7f89f9ea75dc9c50b5e4c4296db4a3d701
	https://git.kernel.org/stable/c/6190db312b8230813f529f014b26247c6d9800d0