CyberRota Analysis
AI-GeneratedThe vulnerability affects the qcom-geni UART implementation in the Linux kernel, where improper handling of transmit DMA flushing can lead to an infinite loop of corrupted data transmission. This issue can be triggered from userspace, potentially causing system hangs during operations that involve large writes followed by a flush command. Organizations utilizing affected Linux systems, particularly those relying on qcom-geni UART for serial communication, should prioritize applying the fix to prevent disruptions in data transmission and system stability.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: serial: qcom-geni: fix TX DMA buffer flush When transmit flushing a qcom-geni UART during an ongoing TX DMA, the UART gets stuck infinitely repeating corrupted TX DMA frames. The DMA-mode uart_ops does not provide a flush_buffer callback, so an in-flight transfer can complete after serial core has reset the transmit kfifo, underflowing its length and resubmitting page-sized transfers indefinitely. Add one that stops the transfer and clears tx_remaining and tx_queued. The stop path was also broken: it unmapped the buffer while the serial engine could still read it, and never reset the TX DMA state machine. Cancel the main sequencer command first, then reset the state machine and wait for it before unmapping. Drop the early return so a pending mapping is also cleaned up when the main command is inactive. The bug can be triggered from userspace with a large write immediately followed by TCOFLUSH. A following tcdrain will hang forever. The bug was reproduced and this fix was validated on Arduino Uno Q (QRB2210) using /dev/ttyHS1.