CVE-2024-36936

/// Technical description

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

efi/unaccepted: touch soft lockup during memory accept

Commit 50e782a86c98 ("efi/unaccepted: Fix soft lockups caused by

parallel memory acceptance") has released the spinlock so other CPUs can

do memory acceptance in parallel and not triggers softlockup on other

CPUs.

However the softlock up was intermittent shown up if the memory of the

TD guest is large, and the timeout of softlockup is set to 1 second:

RIP: 0010:_raw_spin_unlock_irqrestore

Call Trace:

? __hrtimer_run_queues

<IRQ>

? hrtimer_interrupt

? watchdog_timer_fn

? __sysvec_apic_timer_interrupt

? __pfx_watchdog_timer_fn

? sysvec_apic_timer_interrupt

</IRQ>

? __hrtimer_run_queues

<TASK>

? hrtimer_interrupt

? asm_sysvec_apic_timer_interrupt

? _raw_spin_unlock_irqrestore

? __sysvec_apic_timer_interrupt

? sysvec_apic_timer_interrupt

accept_memory

try_to_accept_memory

do_huge_pmd_anonymous_page

get_page_from_freelist

__handle_mm_fault

__a

/// 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