CVE-2024-42153

What it actually does

Calling del_timer_sync() from an interrupt context in the i2c-pnx driver triggers a potential deadlock warning because the timer is used to exit wait_for_completion() after a timeout.

Why it matters to the business

Affected Linux systems may encounter kernel warnings or instability during I2C hardware operations, leading to reduced reliability in servers, embedded devices, or any environment relying on this driver.

How an attack unfolds

An attacker with local access triggers I2C interrupts that invoke the ISR path containing the del_timer_sync call; the flaw surfaces as a warning rather than direct code execution or privilege escalation.

How to fix it

Upgrade the Linux kernel to a version containing commit a349e5ab4dc9954746e836cd10b407ce48f9b2f6, which replaces del_timer_sync with wait_for_completion_timeout and removes the related timer code.

How to confirm the fix worked

Inspect the i2c-pnx driver source to confirm the presence of wait_for_completion_timeout and absence of del_timer_sync calls within the interrupt handler.

Typical attack path

1. Obtain local user access on a vulnerable Linux system
2. Perform I2C device operations that activate the pnx interrupt handler
3. Trigger the timer synchronization inside the ISR to surface the deadlock warning

How to detect it

Search kernel logs and dmesg output for warnings referencing del_timer_sync called from interrupt context in the i2c-pnx driver.

What your security team should do

• Apply the kernel fix containing commit a349e5ab4dc9954746e836cd10b407ce48f9b2f6 on all systems using the i2c-pnx driver
• Review kernel logs for del_timer_sync warnings after updates
• Prioritize updates on production systems handling I2C hardware