Executive brief
The Sound Open Firmware (SOF) audio subsystem in the Linux kernel can experience audio processing interruptions when inter-processor communication (IPC) timeouts occur during DSP pipeline state transitions. This patch improves system resilience by allowing the kernel to continue recovering its internal state even when IPC messages fail, preventing audio subsystem hangs and ensuring the DSP can reinitialize properly on next boot.
Technical details
This is a defect fix (not a security vulnerability) in the ASoC SOF IPC4 PCM driver's pipeline trigger logic (sound/soc/sof/ipc4-pcm.c). The vulnerable code would abort pipeline state transitions on IPC errors, leaving the kernel's internal state inconsistent. The fix ignores IPC errors (including -ETIMEDOUT and firmware crash states) and allows the state machine to continue, ensuring correct widget state for DSP reinitialization. The root cause is traced to system scheduling blockage that blocks reply handling outside the SOF stack, though the firmware actually processes the message. Attack vector is not applicable; this is a reliability/robustness issue. Patch was released and backported to stable kernel versions.
Affected products
- Linux Linux kernel multiple versions (see stable backports)
Timeline
- 2026-07-31: disclosed: Patch commit by Mark Brown
- 2026-08-27: patched: Backported to stable versions via Greg Kroah-Hartman