| Message ID | 20240910144607.1441863-1-sean.anderson@linux.dev (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: xilinx: axienet: Fix race in axienet_stop | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Guessing tree name failed - patch did not apply |
On Tue, Sep 10, 2024 at 10:46:07AM -0400, Sean Anderson wrote: > [ 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"). Applied to 6.6.y and 6.1.y, but nothing older as it didn't apply to 5.15.y :( thanks, greg k-h
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);
[ 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(+)