Linux CVE-2026-93042

In the Linux kernel, the following vulnerability has been resolved:

dmaengine: dw-edma: Terminate all descriptors without callbacks

The DMA Engine client documentation says in the "Terminate APIs" section of Documentation/driver-api/dmaengine/client.rst:

"No callback functions will be called for any incomplete transfers."

dw-edma instead calls vchan_cookie_complete() when a deferred STOP reaches the interrupt handler. This schedules a callback for the active descriptor and leaves other issued or submitted descriptors queued. A late callback after dmaengine_terminate_sync() can dereference client state that has already been freed, while leftover descriptors may later restart into reused buffers or leak.

Move all issued and submitted descriptors to the terminated list whenever termination completes. For a pending STOP, do this from both the DONE and ABORT paths. Complete their cookies in order without scheduling callbacks.

A STOP can remain pending until the running transfer raises an interrupt. Make device_synchronize() wait for such a pending STOP to complete before releasing terminated descriptors. Reuse it from free_chan_resources(), then release the remaining virt-dma resources. Sleep instead of busy-polling while waiting, and warn if the existing timeout expires.