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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-74463

i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock

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Status
Published
Published
Updated
Assigning organization
Linux

Description

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).

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • ba92222ed63a12d09120df9b92f56cc990abac19 to < cc111696ef420f6bb552b2526530067977f0b406affected
  • ba92222ed63a12d09120df9b92f56cc990abac19 to < f96a719d9f8a797105ec5cacf568ab128e33391faffected
  • ba92222ed63a12d09120df9b92f56cc990abac19 to < deffad5bb4f8b4f09e46252f24754ddc9960b244affected
  • ba92222ed63a12d09120df9b92f56cc990abac19 to < 14429dc1c756c35e106f01ff09cadccb82f5531daffected
  • ba92222ed63a12d09120df9b92f56cc990abac19 to < b6cb47e186abba85a3b08aa3023067ab82577286affected
  • ba92222ed63a12d09120df9b92f56cc990abac19 to < 19b783335d62e7a2367436a6e1f1b37da1878360affected
  • ba92222ed63a12d09120df9b92f56cc990abac19 to < aa1944b52d6492c48bdd17046578aa0d953546e6affected
  • ba92222ed63a12d09120df9b92f56cc990abac19 to < d99607c888f26e8a4e9fe9772860cef4aff86bb4affected

Linux Linux

Default version status: affected

  • 4.1affected
  • 0 to < 4.1unaffected
  • 5.10.265 to ≤ 5.10.*unaffected
  • 5.15.216 to ≤ 5.15.*unaffected
  • 6.1.183 to ≤ 6.1.*unaffected
  • 6.6.151 to ≤ 6.6.*unaffected
  • 6.12.103 to ≤ 6.12.*unaffected
  • 6.18.44 to ≤ 6.18.*unaffected
  • 7.1.8 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References