Bug 2426086 (CVE-2022-50870)

Summary: CVE-2022-50870 kernel: powerpc/rtas: avoid device tree lookups in rtas_os_term()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-12-30 13:07:55 UTC 
In the Linux kernel, the following vulnerability has been resolved:

powerpc/rtas: avoid device tree lookups in rtas_os_term()

rtas_os_term() 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 devtree_lock is held, rtas_os_term() 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 of_property_read_bool() since it
is a boolean property, not an RTAS function token.

[mpe: Incorporate suggested change from Nick]
Comment 1 Alexander B 2025-12-31 10:17:25 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025123050-CVE-2022-50870-c90b@gregkh/T