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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)
guessed Create a notification for this product.
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)
guessed Create a notification for this product.
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          "lang": "en",
          "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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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          "url": "https://git.kernel.org/stable/c/d99607c888f26e8a4e9fe9772860cef4aff86bb4"
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    "datePublished": "2026-08-15T12:27:03.176Z",
    "dateReserved": "2026-08-15T05:44:03.901Z",
    "dateUpdated": "2026-08-19T16:37:02.602Z",
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      "title": "i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74463.json",
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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).\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/i2c/busses/i2c-jz4780.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"ba92222ed63a12d09120df9b92f56cc990abac19\",\"lessThan\":\"cc111696ef420f6bb552b2526530067977f0b406\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba92222ed63a12d09120df9b92f56cc990abac19\",\"lessThan\":\"f96a719d9f8a797105ec5cacf568ab128e33391f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba92222ed63a12d09120df9b92f56cc990abac19\",\"lessThan\":\"deffad5bb4f8b4f09e46252f24754ddc9960b244\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba92222ed63a12d09120df9b92f56cc990abac19\",\"lessThan\":\"14429dc1c756c35e106f01ff09cadccb82f5531d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba92222ed63a12d09120df9b92f56cc990abac19\",\"lessThan\":\"b6cb47e186abba85a3b08aa3023067ab82577286\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba92222ed63a12d09120df9b92f56cc990abac19\",\"lessThan\":\"19b783335d62e7a2367436a6e1f1b37da1878360\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba92222ed63a12d09120df9b92f56cc990abac19\",\"lessThan\":\"aa1944b52d6492c48bdd17046578aa0d953546e6\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ba92222ed63a12d09120df9b92f56cc990abac19\",\"lessThan\":\"d99607c888f26e8a4e9fe9772860cef4aff86bb4\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/i2c/busses/i2c-jz4780.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.1\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.1\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.265\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.216\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.183\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.151\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.103\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.44\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.8\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/14429dc1c756c35e106f01ff09cadccb82f5531d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/19b783335d62e7a2367436a6e1f1b37da1878360\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/aa1944b52d6492c48bdd17046578aa0d953546e6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b6cb47e186abba85a3b08aa3023067ab82577286\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cc111696ef420f6bb552b2526530067977f0b406\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d99607c888f26e8a4e9fe9772860cef4aff86bb4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/deffad5bb4f8b4f09e46252f24754ddc9960b244\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f96a719d9f8a797105ec5cacf568ab128e33391f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-21T11:32:58+00:00",
      "cve": "CVE-2026-74463",
      "id": "CVE-2026-74463",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74463.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-31T16:24:53Z",
      "cve": "CVE-2026-74463",
      "id": "CVE-2026-74463",
      "initial_release_date": "2026-08-15T23:52:32Z",
      "product_status:known_affected": "265",
      "product_status:known_not_affected": "97",
      "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": "4"
    }
  }
}



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