6.11-stable review patch. If anyone has any objections, please let me know.
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From: Suraj Gupta suraj.gupta2@amd.com
[ 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! <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.
Fixes: 6a91b846af85 ("net: axienet: Introduce dmaengine support") Signed-off-by: Suraj Gupta suraj.gupta2@amd.com Link: https://patch.msgid.link/20241030062533.2527042-2-suraj.gupta2@amd.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 0c4c57e7fddc2..877f190e3af4e 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: