Executive brief
A memory leak vulnerability was identified in the Linux kernel's Rust implementation for Pulse Width Modulation (PWM) chips. PWM chips are hardware components used to control power delivery to devices like fans, LEDs, or motors. If the system encounters an error while setting up one of these chips, it may fail to release allocated memory, potentially leading to system instability or resource exhaustion over time.
Technical details
A memory leak exists in the Rust PWM abstraction within the Linux kernel. When a PWM chip is initialized via `pwmchip_alloc()`, the allocated device acquires an initial reference count. If the subsequent `__pinned_init()` call fails, the kernel returns an error without invoking `pwmchip_put()`, leaving the allocated `pwm_chip` structure in memory with no remaining references to it. This is a classic reference counting error on an error path. The fix introduces an `inspect_err` block to ensure `pwmchip_put()` is called if initialization fails. Exploitation would likely require the ability to trigger repeated initialization failures of PWM devices, which generally requires local administrative or physical access.
Affected products
- Linux Linux Kernel Versions using Rust PWM abstractions prior to the fix
Timeline
- 2026-01-02: other: Patch authored
- 2026-05-27: disclosed: CVE published