CVE-2026-74463 (GCVE-0-2026-74463)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-19 16:37
VLAI
Title
i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock
Summary
In the Linux kernel, the following vulnerability has been resolved: i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock Fix a severe AB/BA deadlock between the Common Clock Framework (CCF) and the I2C adapter lock, which triggers when an I2C-controlled clock generator client (like the Si5351) is registered or modified under the CCF. During an i2c client clock (generator) frequency change, the CCF acquires its global 'prepare_lock' mutex and the driver calls i2c_transfer() to update the client's chip registers, stalling for the adapter's I2C bus lock. Concurrently, an independent, parallel transfer on the same bus (e.g., a GPIO expander handling LEDs) can hold the I2C adapter lock. Inside this parallel transfer path, jz4780_i2c_set_speed() calls clk_get_rate() on the host controller's input clock to calculate bus timings. This call attempts to acquire the blocked CCF 'prepare_lock', creating a circular dependency that freezes the system. The jz4780 host controller clock itself is static and never changes at runtime. However, calling clk_get_rate() inside the active transfer path introduces an unnecessary dependency on the CCF internal locks. Eliminate this synchronous clk_get_rate() call from the active transfer path by caching the static host peripheral clock rate once - inside the private jz4780_i2c structure during jz4780_i2c_probe(). Update jz4780_i2c_set_speed() to use this cached value, safely decoupling active I2C transactions from the CCF internal locks without any risk of stale timings. Assisted-by web based Google AI (pinpointing the bug and writing the message).
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: ba92222ed63a12d09120df9b92f56cc990abac19 , < cc111696ef420f6bb552b2526530067977f0b406 (git)
Affected: ba92222ed63a12d09120df9b92f56cc990abac19 , < f96a719d9f8a797105ec5cacf568ab128e33391f (git)
Affected: ba92222ed63a12d09120df9b92f56cc990abac19 , < deffad5bb4f8b4f09e46252f24754ddc9960b244 (git)
Affected: ba92222ed63a12d09120df9b92f56cc990abac19 , < 14429dc1c756c35e106f01ff09cadccb82f5531d (git)
Affected: ba92222ed63a12d09120df9b92f56cc990abac19 , < b6cb47e186abba85a3b08aa3023067ab82577286 (git)
Affected: ba92222ed63a12d09120df9b92f56cc990abac19 , < 19b783335d62e7a2367436a6e1f1b37da1878360 (git)
Affected: ba92222ed63a12d09120df9b92f56cc990abac19 , < aa1944b52d6492c48bdd17046578aa0d953546e6 (git)
Affected: ba92222ed63a12d09120df9b92f56cc990abac19 , < d99607c888f26e8a4e9fe9772860cef4aff86bb4 (git)
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Linux Linux Affected: 4.1
Unaffected: 0 , < 4.1 (semver)
Unaffected: 5.10.265 , ≤ 5.10.* (semver)
Unaffected: 5.15.216 , ≤ 5.15.* (semver)
Unaffected: 6.1.183 , ≤ 6.1.* (semver)
Unaffected: 6.6.151 , ≤ 6.6.* (semver)
Unaffected: 6.12.103 , ≤ 6.12.* (semver)
Unaffected: 6.18.44 , ≤ 6.18.* (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ni2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock\n\nFix a severe AB/BA deadlock between the Common Clock Framework (CCF)\nand the I2C adapter lock, which triggers when an I2C-controlled clock\ngenerator client (like the Si5351) is registered or modified under the CCF.\n\nDuring an i2c client clock (generator) frequency change, the CCF acquires its global\n\u0027prepare_lock\u0027 mutex and the driver calls i2c_transfer() to update the client\u0027s\nchip registers, stalling for the adapter\u0027s I2C bus lock.\n\nConcurrently, an independent, parallel transfer on the same bus (e.g., a GPIO\nexpander handling LEDs) can hold the I2C adapter lock. Inside this parallel\ntransfer path, jz4780_i2c_set_speed() calls clk_get_rate() on the host\ncontroller\u0027s input clock to calculate bus timings. This call attempts to acquire\nthe blocked CCF \u0027prepare_lock\u0027, creating a circular dependency that freezes\nthe system.\n\nThe jz4780 host controller clock itself is static and never changes at runtime.\n\nHowever, calling clk_get_rate() inside the active transfer path introduces\nan unnecessary dependency on the CCF internal locks.\n\nEliminate this synchronous clk_get_rate() call from the active transfer\npath by caching the static host peripheral clock rate once - inside the private\njz4780_i2c structure during jz4780_i2c_probe(). Update jz4780_i2c_set_speed()\nto use this cached value, safely decoupling active I2C transactions from the\nCCF internal locks without any risk of stale timings.\n\nAssisted-by web based Google AI (pinpointing the bug and writing the message)."
          }
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        "id": "CVE-2026-74463",
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        "metrics": {},
        "published": "2026-08-15T13:17:50.963",
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        "vulnStatus": "Received"
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      "initial_release_date": "2026-08-15T23:52:32Z",
      "product_status:known_affected": "209",
      "product_status:known_not_affected": "153",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74463",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74463.json",
      "version": "5"
    }
  }
}



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Tags
Taxonomy of the tags.





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

Author Source Type Date Other

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.


Detection rules are retrieved from Rulezet.


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.