CVE-2026-93251

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ACPI: bus: Introduce acpi_bus_get_primary_device()<br /> <br /> The function used for obtaining the first "physical" device for which<br /> the given ACPI one is the ACPI companion, acpi_get_first_physical_node(),<br /> may return a stale device pointer (mostly in theory) because<br /> acpi_unbind_one() may run as a whole after dropping the ACPI device&amp;#39;s<br /> physical_node_lock in acpi_get_first_physical_node() and before it<br /> returns. The last reference to the "physical" device may be dropped<br /> then before the pointer to it is returned to the caller.<br /> <br /> If that happens and the acpi_get_first_physical_node() caller invokes<br /> get_device() on the pointer obtained from it, which is done by the<br /> majority of its callers, a use-after-free will occur.<br /> <br /> To prepare for addressing this problem, introduce a new function for<br /> getting the first "physical" device associated with the given ACPI one<br /> (the "primary physical device") that will also reference count the<br /> device in question before returning a pointer to it.<br /> <br /> Make that new function and acpi_get_first_physical_node() share the<br /> physical node list lookup code.<br /> <br /> No intentional functional impact.