CVE-2023-54026 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
opp: Fix use-after-free in lazy_opp_tables after probe deferral
When dev_pm_opp_of_find_icc_paths() in _allocate_opp_table() returns -EPROBE_DEFER, the opp_table is freed again, to wait until all the interconnect paths are available.
However, if the OPP table is using required-opps then it may already have been added to the global lazy_opp_tables list. The error path does not remove the opp_table from the list again.
This can cause crashes later when the provider of the required-opps is added, since we will iterate over OPP tables that have already been freed. E.g.:
Unable to handle kernel NULL pointer dereference when read CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted 6.4.0-rc3 PC is at _of_add_opp_table_v2 (include/linux/of.h:949 drivers/opp/of.c:98 drivers/opp/of.c:344 drivers/opp/of.c:404 drivers/opp/of.c:1032) -> lazy_link_required_opp_table()
Fix this by calling _of_clear_opp_table() to remove the opp_table from the list and clear other allocated resources. While at it, also add the missing mutex_destroy() calls in the error path.
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Analysis
by VulDB Data Team • 12/26/2025
This vulnerability exists in the linux kernel's power management subsystem specifically within the operating point (opp) framework responsible for managing device power states and frequencies. The flaw manifests when the device power management opp_of_find_icc_paths function encounters probe deferral conditions during hardware initialization. When _allocate_opp_table() returns an -EPROBE_DEFER error code, the system attempts to free the opp_table structure to wait for interconnect paths to become available. However, the error handling path fails to properly clean up all references to the freed structure, particularly when the opp_table has been added to the global lazy_opp_tables list due to required-opps dependencies.
The technical implementation issue stems from improper resource management in the error path of the opp table allocation process. When a device's power management table requires other power domains or interconnect paths that haven't been initialized yet, the system defers the probe operation. During this deferral, the opp_table structure gets freed but remains in the global lazy_opp_tables list, creating a dangling pointer scenario. This violates the fundamental principle of memory safety where freed memory should not be accessed by subsequent operations. The specific code path leads to kernel NULL pointer dereference crashes when the system later attempts to process the required-opps provider that eventually becomes available, causing the lazy_link_required_opp_table() function to iterate over already-freed structures.
The operational impact of this vulnerability represents a critical reliability issue that can lead to kernel panics and system crashes during device initialization sequences. The vulnerability affects any system using the linux kernel's power management framework where devices have required-opps dependencies, potentially causing complete system instability. This type of use-after-free vulnerability aligns with CWE-416, which describes the use of memory after it has been freed, and can be classified under ATT&CK technique T1490 for resource hijacking through kernel memory corruption. The crash occurs in kernel space during normal operation when hardware drivers are being probed, making it particularly dangerous as it can affect system boot processes and device enumeration.
The fix implemented addresses the root cause by ensuring proper cleanup of all references to the freed opp_table structure. The solution involves calling _of_clear_opp_table() to remove the opp_table from the global lazy_opp_tables list and clear other allocated resources, preventing the dangling pointer scenario. Additionally, the fix adds missing mutex_destroy() calls in the error path to prevent potential deadlocks or resource leaks during cleanup operations. This remediation follows proper resource management practices and ensures that all allocated memory and synchronization primitives are properly released regardless of execution path taken during error conditions. The fix specifically targets the lazy_opp_tables list management and ensures that when an opp_table is freed due to probe deferral, it is completely removed from all global data structures that might reference it later.