[ Upstream commit 858430db28a5f5a11f8faa3a6fa805438e6f0851 ]

axienet_dma_err_handler can race with axienet_stop in the following manner:

CPU 1 CPU 2 ====================== ================== axienet_stop() napi_disable() axienet_dma_stop() axienet_dma_err_handler() napi_disable() axienet_dma_stop() axienet_dma_start() napi_enable() cancel_work_sync() free_irq()

Fix this by setting a flag in axienet_stop telling axienet_dma_err_handler not to bother doing anything. I chose not to use disable_work_sync to allow for easier backporting.

Signed-off-by: Sean Anderson sean.anderson@linux.dev Fixes: 8a3b7a252dca ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Link: https://patch.msgid.link/20240903175141.4132898-1-sean.anderson@linux.dev Signed-off-by: Jakub Kicinski kuba@kernel.org [ Adjusted to apply before dmaengine support ] Signed-off-by: Sean Anderson sean.anderson@linux.dev --- This patch is adjusted to apply to v6.6 kernels and earlier, which do not contain commit 6a91b846af85 ("net: axienet: Introduce dmaengine support").

drivers/net/ethernet/xilinx/xilinx_axienet.h | 3 +++ drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 8 ++++++++ 2 files changed, 11 insertions(+)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h index f09f10f17d7e..2facbdfbb319 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet.h +++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h @@ -419,6 +419,8 @@ struct axidma_bd { * @tx_bytes: TX byte count for statistics * @tx_stat_sync: Synchronization object for TX stats * @dma_err_task: Work structure to process Axi DMA errors + * @stopping: Set when @dma_err_task shouldn't do anything because we are + * about to stop the device. * @tx_irq: Axidma TX IRQ number * @rx_irq: Axidma RX IRQ number * @eth_irq: Ethernet core IRQ number @@ -481,6 +483,7 @@ struct axienet_local { struct u64_stats_sync tx_stat_sync;

struct work_struct dma_err_task; + bool stopping;

int tx_irq; int rx_irq; diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 144feb7a2fda..65d7aaad43fe 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -1162,6 +1162,7 @@ static int axienet_open(struct net_device *ndev) phylink_start(lp->phylink);

/* Enable worker thread for Axi DMA error handling */ + lp->stopping = false; INIT_WORK(&lp->dma_err_task, axienet_dma_err_handler);

napi_enable(&lp->napi_rx); @@ -1217,6 +1218,9 @@ static int axienet_stop(struct net_device *ndev)

dev_dbg(&ndev->dev, "axienet_close()\n");

+ WRITE_ONCE(lp->stopping, true); + flush_work(&lp->dma_err_task); + napi_disable(&lp->napi_tx); napi_disable(&lp->napi_rx);

@@ -1761,6 +1765,10 @@ static void axienet_dma_err_handler(struct work_struct *work) dma_err_task); struct net_device *ndev = lp->ndev;

+ /* Don't bother if we are going to stop anyway */ + if (READ_ONCE(lp->stopping)) + return; + napi_disable(&lp->napi_tx); napi_disable(&lp->napi_rx);