CVE-2026-93123

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

serial: qcom-geni: do not advance stale DMA completions

The qcom GENI serial DMA TX completion path advances the transmit fifo by

the number of bytes recorded in port->tx_remaining.

If uart_flush_buffer() runs after the hardware has completed a DMA

transfer but before the DMA completion interrupt has been handled, the

serial core resets the transmit fifo while port->tx_remaining still

describes the old DMA transfer.

A previous fix avoided advancing an empty fifo by checking that the fifo

length is at least tx_remaining. That still does not distinguish the old

DMA payload from new bytes written after the flush. If userspace writes

new data before the stale DMA completion interrupt is handled, the fifo

can again contain at least tx_remaining bytes and the stale completion

can advance and discard those new bytes.

Mark an in-flight DMA transfer stale when the transmit fifo is flushed.

The later completion still unprepares the original DMA mapping using the

saved length, but it no longer advances the transmit fifo.