CVE-2023-53070

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ACPI: PPTT: Fix to avoid sleep in the atomic context when PPTT is absent

Commit 0c80f9e165f8 ("ACPI: PPTT: Leave the table mapped for the runtime usage")

enabled to map PPTT once on the first invocation of acpi_get_pptt() and

never unmapped the same allowing it to be used at runtime with out the

hassle of mapping and unmapping the table. This was needed to fetch LLC

information from the PPTT in the cpuhotplug path which is executed in

the atomic context as the acpi_get_table() might sleep waiting for a

mutex.

However it missed to handle the case when there is no PPTT on the system

which results in acpi_get_pptt() being called from all the secondary

CPUs attempting to fetch the LLC information in the atomic context

without knowing the absence of PPTT resulting in the splat like below:

| BUG: sleeping function called from invalid context at kernel/locking/semaphore.c:164

| in_atomic(): 1, irqs_disabled(): 1, non_bl

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References