What’s Vulnerable › Vulnerabilities

CVE-2021-47567: powerpc/32: Fix hardlockup on vmap stack overflow

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-05-24 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: powerpc/32: Fix hardlockup on vmap stack overflow Since the commit c118c7303ad5 ("powerpc/32: Fix vmap stack - Do not activate MMU before reading task struct") a vmap stack overflow results in a hard lockup. This is because emergency_ctx is still addressed with its virtual address allthough data MMU is not active anymore at that time. Fix it by using a physical address instead.

Affected products

• Linux kernel: from 5.9.5 before 5.10.83; from 5.11 before 5.15.6; 5.16-rc1, 5.16-rc2 — fixed in 5.10.83, 5.15.6

How to fix

Upgrade to a fixed version: Linux kernel 5.10.83, 5.15.6. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/5bb60ea611db1e04814426ed4bd1c95d1487678e
• https://git.kernel.org/stable/c/c4e3ff8b8b1d54f0c755670174c453b06e17114b
• https://git.kernel.org/stable/c/dfe906da9a1abebdebe8b15bb3e66a2578f6c4c7
• https://git.kernel.org/stable/c/5bb60ea611db1e04814426ed4bd1c95d1487678e
• https://git.kernel.org/stable/c/c4e3ff8b8b1d54f0c755670174c453b06e17114b
• https://git.kernel.org/stable/c/dfe906da9a1abebdebe8b15bb3e66a2578f6c4c7

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