In the Linux kernel, the following vulnerability has been resolved: powerpc/rtas: avoid device tree lookups in rtasosterm() rtasosterm() is called during panic. Its behavior depends on a couple of conditions in the /rtas node of the device tree, the traversal of which entails locking and local IRQ state changes. If the kernel panics while devtreelock is held, rtasosterm() as currently written could hang. Instead of discovering the relevant characteristics at panic time, cache them in file-static variables at boot. Note the lookup for "ibm,extended-os-term" is converted to ofpropertyreadbool() since it is a boolean property, not an RTAS function token. [mpe: Incorporate suggested change from Nick]