Bug 2327386 (CVE-2024-53075)

Summary: CVE-2024-53075 kernel: riscv: Prevent a bad reference count on CPU nodes
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Bug Depends On: 2327518    
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Description OSIDB Bzimport 2024-11-19 18:04:31 UTC 
In the Linux kernel, the following vulnerability has been resolved:

riscv: Prevent a bad reference count on CPU nodes

When populating cache leaves we previously fetched the CPU device node
at the very beginning. But when ACPI is enabled we go through a
specific branch which returns early and does not call 'of_node_put' for
the node that was acquired.

Since we are not using a CPU device node for the ACPI code anyways, we
can simply move the initialization of it just passed the ACPI block, and
we are guaranteed to have an 'of_node_put' call for the acquired node.
This prevents a bad reference count of the CPU device node.

Moreover, the previous function did not check for errors when acquiring
the device node, so a return -ENOENT has been added for that case.
Comment 1 Robb Gatica 2024-11-19 20:43:15 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024111924-CVE-2024-53075-2e34@gregkh/T