Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (pmbus) Fix passing events to regulator core
Sashiko reports:
Commit 754bd2b4a084 (“hwmon: (pmbus/core) Protect regulator operations with mutex”) introduced a worker to batch regulator events over time using atomic_or(). The delayed worker then passes the combined bitmask unmodified to regulator_notifier_call_chain().
The core regulator subsystem’s regulator_handle_critical() function evaluates the event parameter using a strict switch statement. If multiple distinct faults occur before the worker runs (e.g., REGULATOR_EVENT_UNDER_VOLTAGE | REGULATOR_EVENT_OVER_CURRENT), the combined bitmask fails to match any case. This leaves the reason as NULL and completely bypasses the critical hw_protection_trigger().
Fix the problem by passing events bit by bit to the regulator event handler.
Details
- Affected product:
- Debian 10 ELS
- Affected packages:
- linux @ 4.19.0