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CVE Record

CVE-2022-49229: ptp: unregister virtual clocks when unregistering physical clock.

In the Linux kernel, the following vulnerability has been resolved: ptp: unregister virtual clocks when unregistering physical clock. When unregistering a physical clock which has some virtual clocks, unregister the virtual clocks with it. This fixes the following oops, which can be triggered by unloading a driver providing a PTP clock when it has enabled virtual clocks: BUG: unable to handle page fault for address: ffffffffc04fc4d8 Oops: 0000 [#1] PREEMPT SMP NOPTI RIP: 0010:ptp_vclock_read+0x31/0xb0 Call Trace: timecounter_read+0xf/0x50 ptp_vclock_refresh+0x2c/0x50 ? ptp_clock_release+0x40/0x40 ptp_aux_kworker+0x17/0x30 kthread_worker_fn+0x9b/0x240 ? kthread_should_park+0x30/0x30 kthread+0xe2/0x110 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x22/0x30

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can crash a system when a Precision Time Protocol physical clock driver is unloaded while virtual PTP clocks are still active. The business impact is mainly availability risk on systems using PTP timing features, such as time-sensitive infrastructure. Public sources do not show active exploitation.

Executive priority

Address during normal vulnerability remediation unless affected systems provide critical timing services. Escalate priority for telecom, trading, industrial, or infrastructure environments where a kernel crash could disrupt operations. No source provided evidence of active exploitation.

Technical view

The PTP subsystem failed to unregister virtual clocks when unregistering the physical clock. That left kernel work able to call ptp_vclock_read after the backing clock driver was unloaded, causing a page fault/oops. The CVE references stable kernel fixes for this cleanup behavior.

Likely exposure

Exposure is likely limited to Linux systems using PTP hardware clocks with virtual clocks enabled. The source bundle lists Linux 5.14-era affected code and fixes in stable branches, including 5.15.33, 5.16.19, 5.17.2, and 5.18 references. Confirm exact distro backports with vendor advisories.

Exploitation context

The documented trigger is unloading a driver that provides a PTP clock while virtual clocks exist. Sources do not indicate remote exploitation, privilege requirements, public exploit code, or CISA KEV listing. Treat this primarily as a local or operational denial-of-service condition unless vendor guidance says otherwise.

Researcher notes

The public record lacks CVSS, CWE, and detailed exploitability analysis. The issue is clearly a lifetime cleanup bug in Linux PTP virtual clock handling. Distro-specific impact may differ because kernel vendors commonly backport fixes without changing upstream version numbers.

Mitigation direction

  • Update to a vendor kernel containing the referenced PTP unregister fixes.
  • Check distribution advisories for backported fixes and affected package versions.
  • Until patched, avoid unloading PTP clock drivers while virtual clocks are enabled.
  • Prioritize systems where PTP timing supports critical operations.

Validation and detection

  • Inventory Linux systems using PTP hardware clocks or virtual PTP clocks.
  • Compare running kernel packages against vendor fixed versions or backport notes.
  • Review kernel changelogs for the referenced PTP virtual clock unregister fix.
  • Check logs for PTP-related kernel oops or page fault messages.
Prepared
Confidence
medium
Sources
6

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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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
3Timeline events
0ADP providers
5Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux73f37068d540eba5f93ba3a0019bf479d35ebd76, 73f37068d540eba5f93ba3a0019bf479d35ebd76, 73f37068d540eba5f93ba3a0019bf479d35ebd76, 73f37068d540eba5f93ba3a0019bf479d35ebd76unaffected
LinuxLinux5.14, 0, 5.15.33, 5.16.19, 5.17.2, 5.18affected
Weakness

CWE details

No CWE listed

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