6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sean Anderson <sean.anderson@xxxxxxxxx>
commit 858430db28a5f5a11f8faa3a6fa805438e6f0851 upstream.
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@xxxxxxxxx>
Fixes: 8a3b7a252dca ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver")
Link: https://patch.msgid.link/20240903175141.4132898-1-sean.anderson@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
[ Adjusted to apply before dmaengine support ]
Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/xilinx/xilinx_axienet.h | 3 +++
drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 8 ++++++++
2 files changed, 11 insertions(+)
--- 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;
--- 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_devic
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_devic
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(stru
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);
