From a3d95bf7c4c5f5b9f392957714b321ba2dc4e583 Mon Sep 17 00:00:00 2001 From: Suraj Gupta Date: Wed, 26 Feb 2025 22:49:14 +0900 Subject: [PATCH] net: xilinx: axienet: Enqueue Tx packets in dql before dmaengine starts BugLink: https://bugs.launchpad.net/bugs/2100292 [ Upstream commit 5ccdcdf186aec6b9111845fd37e1757e9b413e2f ] 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! 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 Start dmaengine after enqueue in dql fixes the crash. Fixes: 6a91b846af85 ("net: axienet: Introduce dmaengine support") Signed-off-by: Suraj Gupta Link: https://patch.msgid.link/20241030062533.2527042-2-suraj.gupta2@amd.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin CVE-2024-50297 Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 4d4b23b2a181..68095d4ffeb2 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -862,13 +862,13 @@ axienet_start_xmit_dmaengine(struct sk_buff *skb, struct net_device *ndev) skbuf_dma->sg_len = sg_len; dma_tx_desc->callback_param = lp; dma_tx_desc->callback_result = axienet_dma_tx_cb; - dmaengine_submit(dma_tx_desc); - dma_async_issue_pending(lp->tx_chan); txq = skb_get_tx_queue(lp->ndev, skb); netdev_tx_sent_queue(txq, skb->len); netif_txq_maybe_stop(txq, CIRC_SPACE(lp->tx_ring_head, lp->tx_ring_tail, TX_BD_NUM_MAX), MAX_SKB_FRAGS + 1, 2 * MAX_SKB_FRAGS); + dmaengine_submit(dma_tx_desc); + dma_async_issue_pending(lp->tx_chan); return NETDEV_TX_OK; xmit_error_unmap_sg: