CVE-2021-47006: ARM: 9064/1: hw_breakpoint: Do not directly check the event's overflow_handler hook

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-02-28 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: ARM: 9064/1: hw_breakpoint: Do not directly check the event's overflow_handler hook The commit 1879445dfa7b ("perf/core: Set event's default ::overflow_handler()") set a default event->overflow_handler in perf_event_alloc(), and replace the check event->overflow_handler with is_default_overflow_handler(), but one is missing. Currently, the bp->overflow_handler can not be NULL. As a result, enable_single_step() is always not invoked. Comments from Zhen Lei: https://patchwork.kernel.org/project/linux-arm-kernel/patch/20210207105934.2001-1-thunder.leizhen@huawei.com/

Affected products

Linux kernel: from 4.7 before 4.9.269; from 4.10 before 4.14.233; from 4.15 before 4.19.191; from 4.20 before 5.4.120; from 5.5 before 5.10.38; from 5.11 before 5.11.22 — fixed in 4.14.233, 4.19.191, 4.9.269, 5.10.38, 5.11.22, 5.12.5

How to fix

Upgrade to a fixed version: Linux kernel 4.14.233, 4.19.191, 4.9.269, 5.10.38. Check the vendor advisory for mitigations.

References

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