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CVE-2024-36936 Detail

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 __alloc_pages __folio_alloc ? __tdx_hypercall handle_mm_fault vma_alloc_folio do_user_addr_fault do_huge_pmd_anonymous_page exc_page_fault ? __do_huge_pmd_anonymous_page asm_exc_page_fault __handle_mm_fault When the local irq is enabled at the end of accept_memory(), the softlockup detects that the watchdog on single CPU has not been fed for a while. That is to say, even other CPUs will not be blocked by spinlock, the current CPU might be stunk with local irq disabled for a while, which hurts not only nmi watchdog but also softlockup. Chao Gao pointed out that the memory accept could be time costly and there was similar report before. Thus to avoid any softlocup detection during this stage, give the softlockup a flag to skip the timeout check at the end of accept_memory(), by invoking touch_softlockup_watchdog().


Metrics

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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
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Hyperlink Resource
https://git.kernel.org/stable/c/1c5a1627f48105cbab81d25ec2f72232bfaa8185
https://git.kernel.org/stable/c/781e34b736014188ba9e46a71535237313dcda81
https://git.kernel.org/stable/c/e115c1b5de55a105c75aba8eb08301c075fa4ef4

Weakness Enumeration

CWE-ID CWE Name Source

Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2024-36936
NVD Published Date:
05/30/2024
NVD Last Modified:
10/10/2024
Source:
kernel.org