{"api_version":"1","generated_at":"2026-08-15T15:08:01+00:00","cve":"CVE-2026-74463","urls":{"html":"https://cve.report/CVE-2026-74463","api":"https://cve.report/api/cve/CVE-2026-74463.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74463","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74463"},"summary":{"title":"i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock","description":"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'prepare_lock' mutex and the driver calls i2c_transfer() to update the client's\nchip registers, stalling for the adapter's 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's input clock to calculate bus timings. This call attempts to acquire\nthe blocked CCF 'prepare_lock', 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).","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 13:17:50","updated_at":"2026-08-15 13:17:50"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/b6cb47e186abba85a3b08aa3023067ab82577286","name":"https://git.kernel.org/stable/c/b6cb47e186abba85a3b08aa3023067ab82577286","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/14429dc1c756c35e106f01ff09cadccb82f5531d","name":"https://git.kernel.org/stable/c/14429dc1c756c35e106f01ff09cadccb82f5531d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/aa1944b52d6492c48bdd17046578aa0d953546e6","name":"https://git.kernel.org/stable/c/aa1944b52d6492c48bdd17046578aa0d953546e6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d99607c888f26e8a4e9fe9772860cef4aff86bb4","name":"https://git.kernel.org/stable/c/d99607c888f26e8a4e9fe9772860cef4aff86bb4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/19b783335d62e7a2367436a6e1f1b37da1878360","name":"https://git.kernel.org/stable/c/19b783335d62e7a2367436a6e1f1b37da1878360","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74463","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74463","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ba92222ed63a12d09120df9b92f56cc990abac19 14429dc1c756c35e106f01ff09cadccb82f5531d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ba92222ed63a12d09120df9b92f56cc990abac19 b6cb47e186abba85a3b08aa3023067ab82577286 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ba92222ed63a12d09120df9b92f56cc990abac19 19b783335d62e7a2367436a6e1f1b37da1878360 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ba92222ed63a12d09120df9b92f56cc990abac19 aa1944b52d6492c48bdd17046578aa0d953546e6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ba92222ed63a12d09120df9b92f56cc990abac19 d99607c888f26e8a4e9fe9772860cef4aff86bb4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.1","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.1 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.151 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.103 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.44 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.8 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc6 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/i2c/busses/i2c-jz4780.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"14429dc1c756c35e106f01ff09cadccb82f5531d","status":"affected","version":"ba92222ed63a12d09120df9b92f56cc990abac19","versionType":"git"},{"lessThan":"b6cb47e186abba85a3b08aa3023067ab82577286","status":"affected","version":"ba92222ed63a12d09120df9b92f56cc990abac19","versionType":"git"},{"lessThan":"19b783335d62e7a2367436a6e1f1b37da1878360","status":"affected","version":"ba92222ed63a12d09120df9b92f56cc990abac19","versionType":"git"},{"lessThan":"aa1944b52d6492c48bdd17046578aa0d953546e6","status":"affected","version":"ba92222ed63a12d09120df9b92f56cc990abac19","versionType":"git"},{"lessThan":"d99607c888f26e8a4e9fe9772860cef4aff86bb4","status":"affected","version":"ba92222ed63a12d09120df9b92f56cc990abac19","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/i2c/busses/i2c-jz4780.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.1"},{"lessThan":"4.1","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.151","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.103","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.44","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.8","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc6","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.151","versionStartIncluding":"4.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.103","versionStartIncluding":"4.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.44","versionStartIncluding":"4.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.8","versionStartIncluding":"4.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc6","versionStartIncluding":"4.1","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"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'prepare_lock' mutex and the driver calls i2c_transfer() to update the client's\nchip registers, stalling for the adapter's 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's input clock to calculate bus timings. This call attempts to acquire\nthe blocked CCF 'prepare_lock', 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)."}],"providerMetadata":{"dateUpdated":"2026-08-15T12:27:03.176Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/14429dc1c756c35e106f01ff09cadccb82f5531d"},{"url":"https://git.kernel.org/stable/c/b6cb47e186abba85a3b08aa3023067ab82577286"},{"url":"https://git.kernel.org/stable/c/19b783335d62e7a2367436a6e1f1b37da1878360"},{"url":"https://git.kernel.org/stable/c/aa1944b52d6492c48bdd17046578aa0d953546e6"},{"url":"https://git.kernel.org/stable/c/d99607c888f26e8a4e9fe9772860cef4aff86bb4"}],"title":"i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74463","datePublished":"2026-08-15T12:27:03.176Z","dateReserved":"2026-08-15T05:44:03.901Z","dateUpdated":"2026-08-15T12:27:03.176Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 13:17:50","lastModifiedDate":"2026-08-15 13:17:50","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74463","Ordinal":"1","Title":"i2c: jz4780: Cache host clock rate at probe to prevent CCF prepa","CVE":"CVE-2026-74463","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74463","Ordinal":"1","NoteData":"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'prepare_lock' mutex and the driver calls i2c_transfer() to update the client's\nchip registers, stalling for the adapter's 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's input clock to calculate bus timings. This call attempts to acquire\nthe blocked CCF 'prepare_lock', 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).","Type":"Description","Title":"i2c: jz4780: Cache host clock rate at probe to prevent CCF prepa"}]}}}