CVE-2022-49001: riscv: fix race when vmap stack overflow

Severity: high (CVSS 7.0 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: 2024-10-21 · updated 2026-08-04
Weakness: CWE-362

Description

In the Linux kernel, the following vulnerability has been resolved: riscv: fix race when vmap stack overflow Currently, when detecting vmap stack overflow, riscv firstly switches to the so called shadow stack, then use this shadow stack to call the get_overflow_stack() to get the overflow stack. However, there's a race here if two or more harts use the same shadow stack at the same time. To solve this race, we introduce spin_shadow_stack atomic var, which will be swap between its own address and 0 in atomic way, when the var is set, it means the shadow_stack is being used; when the var is cleared, it means the shadow_stack isn't being used. [Palmer: Add AQ to the swap, and also some comments.]

Affected products

Linux kernel: from 5.14 before 5.15.82; from 5.16 before 6.0.12; 6.1-rc1, 6.1-rc2, 6.1-rc3, 6.1-rc4, 6.1-rc5, 6.1-rc6 (+1) — fixed in 5.15.82, 6.0.12

How to fix

Upgrade to a fixed version: Linux kernel 5.15.82, 6.0.12. Check the vendor advisory for mitigations.

References

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