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CVE Record

CVE-2022-50771: rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state()

In the Linux kernel, the following vulnerability has been resolved: rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state() Running rcutorture with non-zero fqs_duration module parameter in a kernel built with CONFIG_PREEMPTION=y results in the following splat: BUG: using __this_cpu_read() in preemptible [00000000] code: rcu_torture_fqs/398 caller is __this_cpu_preempt_check+0x13/0x20 CPU: 3 PID: 398 Comm: rcu_torture_fqs Not tainted 6.0.0-rc1-yoctodev-standard+ Call Trace: <TASK> dump_stack_lvl+0x5b/0x86 dump_stack+0x10/0x16 check_preemption_disabled+0xe5/0xf0 __this_cpu_preempt_check+0x13/0x20 rcu_force_quiescent_state.part.0+0x1c/0x170 rcu_force_quiescent_state+0x1e/0x30 rcu_torture_fqs+0xca/0x160 ? rcu_torture_boost+0x430/0x430 kthread+0x192/0x1d0 ? kthread_complete_and_exit+0x30/0x30 ret_from_fork+0x22/0x30 </TASK> The problem is that rcu_force_quiescent_state() uses __this_cpu_read() in preemptible code instead of the proper raw_cpu_read(). This commit therefore changes __this_cpu_read() to raw_cpu_read().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

CVE-2022-50771 is a Linux kernel RCU bug that triggers a kernel lockdep warning under a specific rcutorture test configuration. The public record does not describe data theft, privilege escalation, remote access, or active exploitation. Business urgency appears low unless your environment runs affected kernels with this testing path enabled.

Executive priority

Treat as routine kernel maintenance, not an emergency, based on current public evidence. Prioritize in normal patch cycles, especially for systems using custom kernels, kernel testing, or preemption-enabled builds.

Technical view

The issue is in rcu_force_quiescent_state(), which used __this_cpu_read() in preemptible code. With CONFIG_PREEMPTION=y and rcutorture using a non-zero fqs_duration parameter, lockdep reports a preemption-related warning. The fix changes the access to raw_cpu_read().

Likely exposure

Exposure appears limited to Linux kernels covered by the CVE affected list and the specific RCU torture-test path. Standard production workloads are not shown in the provided sources as a trigger. Confirm exposure through your distribution’s kernel advisories and backport status.

Exploitation context

No active exploitation is indicated. The source bundle says KEV is false, and the description shows a test-triggered lockdep warning rather than an externally reachable attack path. No public source in the bundle provides exploitability evidence.

Researcher notes

The CVE record maps to several stable kernel commits. The root issue is incorrect per-CPU read usage in preemptible context inside RCU force-quiescent-state logic. The provided evidence does not establish confidentiality, integrity, or availability impact beyond the warning.

Mitigation direction

  • Update to a vendor-supported kernel containing the referenced stable fix commits.
  • Check your Linux distribution advisory for backported fixes and affected package versions.
  • If updates are delayed, avoid enabling rcutorture configurations that trigger this path.
  • Follow vendor guidance; no separate workaround is named in the sources.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and container hosts.
  • Confirm whether the running kernel includes one of the referenced stable commits or vendor backport.
  • Check whether CONFIG_PREEMPTION is enabled on relevant kernels.
  • Review kernel logs for the described lockdep warning during rcutorture testing.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2022-50771 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
7Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxd860d40327dde251d508a234fa00bd0d90fbb656, d860d40327dde251d508a234fa00bd0d90fbb656, d860d40327dde251d508a234fa00bd0d90fbb656, d860d40327dde251d508a234fa00bd0d90fbb656, d860d40327dde251d508a234fa00bd0d90fbb656, d860d40327dde251d508a234fa00bd0d90fbb656unaffected
LinuxLinux3.17, 0, 5.4.229, 5.10.163, 5.15.86, 6.0.16, 6.1.2, 6.2affected
Weakness

CWE details

No CWE listed

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