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

nvdimm: Fix firmware activation deadlock scenarios

Lockdep reports the following deadlock scenarios for CXL root device
power-management, device_prepare(), operations, and device_shutdown()
operations for 'nd_region' devices:

 Chain exists of:
   &nvdimm_region_key --> &nvdimm_bus->reconfig_mutex --> system_transition_mutex

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(system_transition_mutex);
                                lock(&nvdimm_bus->reconfig_mutex);
                                lock(system_transition_mutex);
   lock(&nvdimm_region_key);

 Chain exists of:
   &cxl_nvdimm_bridge_key --> acpi_scan_lock --> &cxl_root_key

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&cxl_root_key);
                                lock(acpi_scan_lock);
                                lock(&cxl_root_key);
   lock(&cxl_nvdimm_bridge_key);

These stem from holding nvdimm_bus_lock() over hibernate_quiet_exec()
which walks the entire system device topology taking device_lock() along
the way. The nvdimm_bus_lock() is protecting against unregistration,
multiple simultaneous ops callers, and preventing activate_show() from
racing activate_store(). For the first 2, the lock is redundant.
Unregistration already flushes all ops users, and sysfs already prevents
multiple threads to be active in an ops handler at the same time. For
the last userspace should already be waiting for its last
activate_store() to complete, and does not need activate_show() to flush
the write side, so this lock usage can be deleted in these attributes.

https://git.kernel.org/stable/c/2f97ebc58d5fc83ca1528cd553fa725472ab3ca8

https://git.kernel.org/stable/c/2fd853fdb40afc052de338693df1372f2ead7be7

https://git.kernel.org/stable/c/641649f31e20df630310f5c22f26c071acc676d4

https://git.kernel.org/stable/c/ceb924ee16b2c8e48dcac3d9ad6be01c40b5a228

https://git.kernel.org/stable/c/e6829d1bd3c4b58296ee9e412f7ed4d6cb390192