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CVE Record

CVE-2024-43876: PCI: rcar: Demote WARN() to dev_warn_ratelimited() in rcar_pcie_wakeup()

In the Linux kernel, the following vulnerability has been resolved: PCI: rcar: Demote WARN() to dev_warn_ratelimited() in rcar_pcie_wakeup() Avoid large backtrace, it is sufficient to warn the user that there has been a link problem. Either the link has failed and the system is in need of maintenance, or the link continues to work and user has been informed. The message from the warning can be looked up in the sources. This makes an actual link issue less verbose. First of all, this controller has a limitation in that the controller driver has to assist the hardware with transition to L1 link state by writing L1IATN to PMCTRL register, the L1 and L0 link state switching is not fully automatic on this controller. In case of an ASMedia ASM1062 PCIe SATA controller which does not support ASPM, on entry to suspend or during platform pm_test, the SATA controller enters D3hot state and the link enters L1 state. If the SATA controller wakes up before rcar_pcie_wakeup() was called and returns to D0, the link returns to L0 before the controller driver even started its transition to L1 link state. At this point, the SATA controller did send an PM_ENTER_L1 DLLP to the PCIe controller and the PCIe controller received it, and the PCIe controller did set PMSR PMEL1RX bit. Once rcar_pcie_wakeup() is called, if the link is already back in L0 state and PMEL1RX bit is set, the controller driver has no way to determine if it should perform the link transition to L1 state, or treat the link as if it is in L0 state. Currently the driver attempts to perform the transition to L1 link state unconditionally, which in this specific case fails with a PMSR L1FAEG poll timeout, however the link still works as it is already back in L0 state. Reduce this warning verbosity. In case the link is really broken, the rcar_pcie_config_access() would fail, otherwise it will succeed and any system with this controller and ASM1062 can suspend without generating a backtrace.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This Linux kernel CVE concerns noisy failure handling in the Renesas R-Car PCIe driver. During suspend or platform power-management testing, a specific PCIe link state race can trigger a large kernel backtrace even when the link still works. The sourced impact is operational noise, not confirmed compromise.

Executive priority

Schedule this with normal kernel maintenance unless affected embedded or edge devices rely heavily on suspend and resume. The available evidence points to reliability and log-noise reduction, not confirmed data exposure or active attack activity.

Technical view

In rcar_pcie_wakeup(), the driver may attempt an L1 transition after the link has already returned to L0 while PMEL1RX is set. That can cause an L1FAEG poll timeout and WARN() backtrace. The kernel fix demotes this to dev_warn_ratelimited(), reducing verbosity for this link problem.

Likely exposure

Exposure appears limited to Linux systems using the Renesas R-Car PCIe controller path, especially configurations like the cited ASMedia ASM1062 PCIe SATA controller during suspend or pm_test. General Linux servers without this hardware path are unlikely to be exposed based on the sources.

Exploitation context

The bundle shows no CISA KEV listing and no cited evidence of active exploitation. The described trigger is a hardware and power-management condition, not a documented remote attack path. Treat exploitability as unproven from the provided evidence.

Researcher notes

The important distinction is that the fix reduces WARN() verbosity; it does not describe a memory corruption primitive, privilege boundary bypass, or attacker-controlled payload. Evidence is incomplete for security impact beyond operational failure handling.

Mitigation direction

  • Check vendor or distribution advisories for kernel updates containing the referenced stable commits.
  • Prioritize affected Renesas R-Car platforms that suspend, resume, or run platform power-management tests.
  • For Debian LTS systems, review the cited Debian announcement and apply the relevant kernel package guidance.
  • If no packaged fix is available, follow vendor guidance rather than applying ad hoc driver changes.

Validation and detection

  • Inventory systems using Renesas R-Car PCIe controller hardware or related board support packages.
  • Compare running kernel versions against vendor advisories and the referenced stable commit history.
  • Review kernel logs for repeated R-Car PCIe wakeup, L1FAEG timeout, or large WARN backtraces.
  • Test suspend and resume behavior after updating, focusing on PCIe SATA devices if present.
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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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
2ADP providers
7Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

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.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux9e14fb714ebf55443dd3449de9ea2ffcf13e562a, 84b576146294c2be702cfcd174eaa74167e276f9, 84b576146294c2be702cfcd174eaa74167e276f9, 84b576146294c2be702cfcd174eaa74167e276f9, 84b576146294c2be702cfcd174eaa74167e276f9unaffected
LinuxLinux5.18, 0, 6.1.103, 6.6.44, 6.10.3, 6.11affected
Weakness

CWE details

No CWE listed

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