In the Linux kernel, the following vulnerability has been resolved: net: xilinx: axienet: Enqueue Tx packets in dql before dmaengine starts Enqueue packets in dql after dma engine starts causes race condition. Tx transfer starts once dma engine is started and may execute dql dequeue in completion before it gets queued. It results in following kernel crash while running iperf stress test: kernel BUG at lib/dynamic_queue_limits.c:99! <snip> Internal error: Oops - BUG: 00000000f2000800 [#1] SMP pc : dql_completed+0x238/0x248 lr : dql_completed+0x3c/0x248 Call trace: dql_completed+0x238/0x248 axienet_dma_tx_cb+0xa0/0x170 xilinx_dma_do_tasklet+0xdc/0x290 tasklet_action_common+0xf8/0x11c tasklet_action+0x30/0x3c handle_softirqs+0xf8/0x230 <snip> Start dmaengine after enqueue in dql fixes the crash.
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.