Device Reference Count Underflow in Linux Kernel Affects DMA Channel Management

CVE-2026-98344

What is CVE-2026-98344?

A vulnerability in the Linux kernel's DMA engine has been identified, leading to a device reference count underflow. This issue arises during the management of DMA channels, specifically when the dma_chan_put() function drops the device reference unconditionally. If certain conditions are met, including the presence of a persistent client and another client cycling through dmaengine_get() and dmaengine_put(), it can lead to a situation where a valid provider module is unloaded prematurely, ultimately returning NULL from dma_find_channel(). The fix ensures that the device reference is only dropped during the last put operation, aligning it with the respective slow-path gets, thereby maintaining proper reference counting integrity.

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