FKIE_CVE-2026-97515

Vulnerability from fkie_nvd - Published: 2026-09-24 17:17 - Updated: 2026-09-24 17:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: i3c: master: svc: Prevent IRQ storm from false SLVSTART on NPCM845 On NPCM845, when a target on the I3C bus gets stuck holding SDA low, the controller reports a false Master Request (MR) in-band interrupt event. The driver handles this by emitting a STOP condition to restore the bus. However, the hardware quirk SVC_I3C_QUIRK_FALSE_SLVSTART indicates that emitting a STOP condition may spuriously set the SLVSTART interrupt status bit. In the Master Request case, this creates a feedback loop: the STOP triggers a new SLVSTART event, the IRQ handler fires again, the controller still reports an MR type, another STOP is emitted, and the cycle repeats indefinitely, resulting in an IRQ storm that can lock up the CPU. Clear the SLVSTART status bit explicitly after emitting the STOP in the Master Request IBI handler when the SVC_I3C_QUIRK_FALSE_SLVSTART quirk is set. This breaks the feedback loop without affecting normal SLVSTART processing, which is already guarded in the top-level IRQ handler by checking that MSTATUS is in SLVREQ state.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1effa3adfe53cb2bb28bf5640a676b791d5ab405
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e9b139c4684ed8593a0b779ca02ea05f460b2eec
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/i3c/master/svc-i3c-master.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e9b139c4684ed8593a0b779ca02ea05f460b2eec",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "1effa3adfe53cb2bb28bf5640a676b791d5ab405",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "6.18.53",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/i3c/master/svc-i3c-master.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ni3c: master: svc: Prevent IRQ storm from false SLVSTART on NPCM845\n\nOn NPCM845, when a target on the I3C bus gets stuck holding SDA low,\nthe controller reports a false Master Request (MR) in-band interrupt\nevent. The driver handles this by emitting a STOP condition to restore\nthe bus.\n\nHowever, the hardware quirk SVC_I3C_QUIRK_FALSE_SLVSTART indicates that\nemitting a STOP condition may spuriously set the SLVSTART interrupt\nstatus bit. In the Master Request case, this creates a feedback loop:\nthe STOP triggers a new SLVSTART event, the IRQ handler fires again,\nthe controller still reports an MR type, another STOP is emitted, and\nthe cycle repeats indefinitely, resulting in an IRQ storm that can lock\nup the CPU.\n\nClear the SLVSTART status bit explicitly after emitting the STOP in the\nMaster Request IBI handler when the SVC_I3C_QUIRK_FALSE_SLVSTART quirk\nis set. This breaks the feedback loop without affecting normal SLVSTART\nprocessing, which is already guarded in the top-level IRQ handler by\nchecking that MSTATUS is in SLVREQ state."
    }
  ],
  "id": "CVE-2026-97515",
  "lastModified": "2026-09-24T17:17:29.440",
  "metrics": {},
  "published": "2026-09-24T17:17:29.440",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1effa3adfe53cb2bb28bf5640a676b791d5ab405"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e9b139c4684ed8593a0b779ca02ea05f460b2eec"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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