CVE-2026-90193 (GCVE-0-2026-90193)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:07 – Updated: 2026-09-17 16:07
VLAI
Title
mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler
Summary
In the Linux kernel, the following vulnerability has been resolved: mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler qcom_cpucp_mbox_irq_fn() calls mbox_chan_received_data() while holding chan->lock. Under PREEMPT_RT, spin_lock_irqsave() is converted to an rt_spinlock (rtmutex-based), which tracks ownership and can sleep. The callback chain triggered by mbox_chan_received_data() eventually reaches mailbox_clear_channel() -> mbox_send_message() -> add_to_rbuf(), which attempts to re-acquire the same chan->lock. Since rtmutex detects the re-entrant lock attempt by the same owner, the thread blocks waiting for a lock it already holds, causing a permanent deadlock. This deadlock manifests as 'irq/N-apss_cpucp_mbox' stuck in D state with the following call trace: rt_spin_lock -> mbox_send_message -> mailbox_clear_channel -> scmi_rx_callback -> mbox_chan_received_data [<- held chan->lock here] Fix by saving chan->cl locally and clearing the HW interrupt register inside the lock, then invoking mbox_chan_received_data() after releasing the lock. This preserves the mutual exclusion for chan->cl access while avoiding the lock re-entrancy that causes the PREEMPT_RT deadlock.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 , < aa482273f32117c3adeba9b1cc945e0b5d33722d (git)
Affected: 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 , < 8b8de6400c86937ed57d680d06d716e167b381de (git)
Affected: 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 , < e40b3edeaf25cd09e9c88edb1ef99373ca37593b (git)
Affected: 0e2a9a03106cd5fa0dbc9047675e7645c55e2669 , < 3690aaa6d18f6775c3e7932fb8af8c5bf6a6b69c (git)
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Linux Linux Affected: 6.11
Unaffected: 0 , < 6.11 (semver)
Unaffected: 6.12.110 , ≤ 6.12.* (semver)
Unaffected: 6.18.52 , ≤ 6.18.* (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/mailbox/qcom-cpucp-mbox.c"
          ],
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          "vendor": "Linux",
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler\n\nqcom_cpucp_mbox_irq_fn() calls mbox_chan_received_data() while holding\nchan-\u003elock. Under PREEMPT_RT, spin_lock_irqsave() is converted to an\nrt_spinlock (rtmutex-based), which tracks ownership and can sleep.\n\nThe callback chain triggered by mbox_chan_received_data() eventually\nreaches mailbox_clear_channel() -\u003e mbox_send_message() -\u003e add_to_rbuf(),\nwhich attempts to re-acquire the same chan-\u003elock. Since rtmutex detects\nthe re-entrant lock attempt by the same owner, the thread blocks waiting\nfor a lock it already holds, causing a permanent deadlock.\n\nThis deadlock manifests as \u0027irq/N-apss_cpucp_mbox\u0027 stuck in D state\nwith the following call trace:\n  rt_spin_lock -\u003e mbox_send_message -\u003e mailbox_clear_channel -\u003e\n  scmi_rx_callback -\u003e mbox_chan_received_data [\u003c- held chan-\u003elock here]\n\nFix by saving chan-\u003ecl locally and clearing the HW interrupt register\ninside the lock, then invoking mbox_chan_received_data() after releasing\nthe lock. This preserves the mutual exclusion for chan-\u003ecl access while\navoiding the lock re-entrancy that causes the PREEMPT_RT deadlock."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-17T16:07:13.672Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/aa482273f32117c3adeba9b1cc945e0b5d33722d"
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        },
        {
          "url": "https://git.kernel.org/stable/c/3690aaa6d18f6775c3e7932fb8af8c5bf6a6b69c"
        }
      ],
      "title": "mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90193",
    "datePublished": "2026-09-17T16:07:13.672Z",
    "dateReserved": "2026-09-11T19:38:34.792Z",
    "dateUpdated": "2026-09-17T16:07:13.672Z",
    "state": "PUBLISHED"
  },
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      "date": "2026-09-25",
      "epss": "0.00209",
      "percentile": "0.09849"
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                    "versionType": "semver"
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler\n\nqcom_cpucp_mbox_irq_fn() calls mbox_chan_received_data() while holding\nchan-\u003elock. Under PREEMPT_RT, spin_lock_irqsave() is converted to an\nrt_spinlock (rtmutex-based), which tracks ownership and can sleep.\n\nThe callback chain triggered by mbox_chan_received_data() eventually\nreaches mailbox_clear_channel() -\u003e mbox_send_message() -\u003e add_to_rbuf(),\nwhich attempts to re-acquire the same chan-\u003elock. Since rtmutex detects\nthe re-entrant lock attempt by the same owner, the thread blocks waiting\nfor a lock it already holds, causing a permanent deadlock.\n\nThis deadlock manifests as \u0027irq/N-apss_cpucp_mbox\u0027 stuck in D state\nwith the following call trace:\n  rt_spin_lock -\u003e mbox_send_message -\u003e mailbox_clear_channel -\u003e\n  scmi_rx_callback -\u003e mbox_chan_received_data [\u003c- held chan-\u003elock here]\n\nFix by saving chan-\u003ecl locally and clearing the HW interrupt register\ninside the lock, then invoking mbox_chan_received_data() after releasing\nthe lock. This preserves the mutual exclusion for chan-\u003ecl access while\navoiding the lock re-entrancy that causes the PREEMPT_RT deadlock."
          }
        ],
        "id": "CVE-2026-90193",
        "lastModified": "2026-09-17T17:17:14.030",
        "metrics": {},
        "published": "2026-09-17T17:17:14.030",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.