CVE-2026-80939: wifi: rtw89: pci: add .shutdown callback to stop rfkill polling on reboot

CVE-2026-80939: wifi: rtw89: pci: add .shutdown callback to stop rfkill polling on reboot

[Greg Kroah-Hartman]

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

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

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

wifi: rtw89: pci: add .shutdown callback to stop rfkill polling on reboot

Since the hardware rfkill polling was introduced, arm64 platforms can
panic with an asynchronous SError during warm reboot:

  SError Interrupt on CPU8, code 0x00000000be000011 -- SError
  Workqueue: events_power_efficient rfkill_poll [rfkill]
    rtw89_pci_ops_read8+0x94/0x160 [rtw89_pci]
    rtw89_core_rfkill_poll+0x50/0x1e0 [rtw89_core]
    rtw89_ops_rfkill_poll+0x40/0x68 [rtw89_core]
    ieee80211_rfkill_poll+0x3c/0x70 [mac80211]
    cfg80211_rfkill_poll+0x40/0x2a0 [cfg80211]
    rfkill_poll+0x30/0x88 [rfkill]
  Kernel panic - not syncing: Asynchronous SError Interrupt

On the reboot path the kernel only runs device_shutdown(), which calls
each driver's .shutdown callback; .remove is not invoked.  The rtw89 PCI
driver had no .shutdown callback, so nothing stopped the rfkill polling
work while the platform was tearing the PCIe link down.  Once the link
is gone, the next MMIO read from the poll handler targets a
non-responding device and is reported as a fatal asynchronous SError on
arm64.

Add rtw89_pci_shutdown(), wired to all rtw89 PCI device drivers, which
sets a new RTW89_FLAG_SHUTDOWN flag (mirroring the USB
RTW89_FLAG_UNPLUGGED pattern).  When the flag is set,
rtw89_ops_rfkill_poll() returns early, so no MMIO read is issued to the
chip after shutdown begins and the SError no longer occurs.

This does not call the full .remove path from .shutdown, to keep the
shutdown handler minimal and avoid running the non-idempotent teardown
twice.

The Linux kernel CVE team has assigned CVE-2026-80939 to this issue.


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

	Issue introduced in 6.12 with commit 0b38e6277aed8a59ccb64fcc1172d962c1f11b4c and fixed in 7.2.4 with commit c1f214dd1351244156deb57761b14190a233aef6
	Issue introduced in 6.12 with commit 0b38e6277aed8a59ccb64fcc1172d962c1f11b4c and fixed in 7.3-rc1 with commit 667c12782aaf8dd3cb2213e528fe63a73cb63345

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-2026-80939
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/realtek/rtw89/core.h
	drivers/net/wireless/realtek/rtw89/mac80211.c
	drivers/net/wireless/realtek/rtw89/pci.c
	drivers/net/wireless/realtek/rtw89/pci.h
	drivers/net/wireless/realtek/rtw89/rtw8851be.c
	drivers/net/wireless/realtek/rtw89/rtw8852ae.c
	drivers/net/wireless/realtek/rtw89/rtw8852be.c
	drivers/net/wireless/realtek/rtw89/rtw8852bte.c
	drivers/net/wireless/realtek/rtw89/rtw8852ce.c
	drivers/net/wireless/realtek/rtw89/rtw8922ae.c
	drivers/net/wireless/realtek/rtw89/rtw8922de.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/c1f214dd1351244156deb57761b14190a233aef6
	https://git.kernel.org/stable/c/667c12782aaf8dd3cb2213e528fe63a73cb63345