CVE-2026-74407: wifi: ath11k: cancel SSR work items during PCI shutdown

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

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

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

wifi: ath11k: cancel SSR work items during PCI shutdown

A reboot can crash the kernel if it overlaps with WLAN firmware crash
recovery (SSR). The crash is a NULL pointer dereference in the MHI teardown
path while freeing DMA-backed MHI contexts.

Simplified trace:
  dma_free_attrs
  mhi_deinit_dev_ctxt [mhi]
  ath11k_pci_power_down [ath11k_pci]
  ath11k_pci_shutdown [ath11k_pci]
  device_shutdown
  kernel_restart

On the host side, SSR is driven by the MHI RDDM callback, which queues
reset_work to perform device recovery. reset_work power-cycles the device
by calling ath11k_hif_power_down() followed by ath11k_hif_power_up(). The
power-down phase deinitializes MHI and frees DMA resources.

Shutdown/reboot runs fully asynchronously with this RDDM-driven SSR
recovery flow. As a result, the shutdown path
(ath11k_pci_shutdown() -> ath11k_pci_power_down()) can race with the SSR
recovery sequence.

Fix this by canceling SSR-related work items during PCI shutdown, marking
the device as unregistering, and serializing the RDDM callback path that
checks and queues reset_work. This ensures that no new SSR recovery work
can be queued once teardown has started, and that any in-flight recovery
work is fully synchronized before device power-down, preventing MHI
teardown and DMA resource freeing from running more than once.

Note: This issue only affects PCI/MHI-based devices. AHB-based ath11k
devices do not queue reset_work in normal SSR flows.

Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-04866.5-QCAHSPSWPL_V1_V2_SILICONZ_IOE-1

The Linux kernel CVE team has assigned CVE-2026-74407 to this issue.


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

	Issue introduced in 5.19 with commit 13da397f884d9c9a3fb6616206eeb6c6ab097287 and fixed in 7.1.5 with commit 53dd29e8aeb2a1b5f079178551836b85fc6b53df
	Issue introduced in 5.19 with commit 13da397f884d9c9a3fb6616206eeb6c6ab097287 and fixed in 7.2-rc1 with commit 8c79aac429b583301f387374ff37c59be671df87

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-2026-74407
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/ath/ath11k/mhi.c
	drivers/net/wireless/ath/ath11k/pci.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/53dd29e8aeb2a1b5f079178551836b85fc6b53df
	https://git.kernel.org/stable/c/8c79aac429b583301f387374ff37c59be671df87