| Message ID | 20220818182948.931712-1-saproj@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [1/2] net: moxa: do not call dma_unmap_single() with null | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Guessing tree name failed - patch did not apply |
On Thu, Aug 18, 2022 at 09:29:47PM +0300, Sergei Antonov wrote: > It fixes a warning during error unwinding: > > WARNING: CPU: 0 PID: 1 at kernel/dma/debug.c:963 check_unmap+0x704/0x980 > DMA-API: moxart-ethernet 92000000.mac: device driver tries to free DMA memory it has not allocated [device address=0x0000000000000000] [size=1600 bytes] > CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0+ #60 > Hardware name: Generic DT based system > unwind_backtrace from show_stack+0x10/0x14 > show_stack from dump_stack_lvl+0x34/0x44 > dump_stack_lvl from __warn+0xbc/0x1f0 > __warn from warn_slowpath_fmt+0x94/0xc8 > warn_slowpath_fmt from check_unmap+0x704/0x980 > check_unmap from debug_dma_unmap_page+0x8c/0x9c > debug_dma_unmap_page from moxart_mac_free_memory+0x3c/0xa8 > moxart_mac_free_memory from moxart_mac_probe+0x190/0x218 > moxart_mac_probe from platform_probe+0x48/0x88 > platform_probe from really_probe+0xc0/0x2e4 > > Fixes: 6c821bd9edc9 ("net: Add MOXA ART SoCs ethernet driver") > Signed-off-by: Sergei Antonov <saproj@gmail.com> This looks correct as it is: Reviewed-by: Andrew Lunn <andrew@lunn.ch> But i do wonder how it go into the situation: for (i = 0; i < RX_DESC_NUM; i++) { desc = priv->rx_desc_base + i * RX_REG_DESC_SIZE; memset(desc, 0, RX_REG_DESC_SIZE); moxart_desc_write(RX_DESC0_DMA_OWN, desc + RX_REG_OFFSET_DESC0); moxart_desc_write(RX_BUF_SIZE & RX_DESC1_BUF_SIZE_MASK, desc + RX_REG_OFFSET_DESC1); priv->rx_buf[i] = priv->rx_buf_base + priv->rx_buf_size * i; priv->rx_mapping[i] = dma_map_single(&ndev->dev, priv->rx_buf[i], priv->rx_buf_size, DMA_FROM_DEVICE); if (dma_mapping_error(&ndev->dev, priv->rx_mapping[i])) netdev_err(ndev, "DMA mapping error\n"); moxart_desc_write(priv->rx_mapping[i], desc + RX_REG_OFFSET_DESC2 + RX_DESC2_ADDRESS_PHYS); moxart_desc_write((uintptr_t)priv->rx_buf[i], desc + RX_REG_OFFSET_DESC2 + RX_DESC2_ADDRESS_VIRT); } There is no way out of this, such that it only allocates some but not all. So maybe there was an dma_mapping_error, it printed: DMA mapping error, but kept going? So maybe another patch would be good, making moxart_mac_setup_desc_ring() return an error when something goes wrong? Andrew
On Thu, 18 Aug 2022 at 22:18, Andrew Lunn <andrew@lunn.ch> wrote: > > On Thu, Aug 18, 2022 at 09:29:47PM +0300, Sergei Antonov wrote: > > It fixes a warning during error unwinding: > > > > WARNING: CPU: 0 PID: 1 at kernel/dma/debug.c:963 check_unmap+0x704/0x980 > > DMA-API: moxart-ethernet 92000000.mac: device driver tries to free DMA memory it has not allocated [device address=0x0000000000000000] [size=1600 bytes] > > CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0+ #60 > > Hardware name: Generic DT based system > > unwind_backtrace from show_stack+0x10/0x14 > > show_stack from dump_stack_lvl+0x34/0x44 > > dump_stack_lvl from __warn+0xbc/0x1f0 > > __warn from warn_slowpath_fmt+0x94/0xc8 > > warn_slowpath_fmt from check_unmap+0x704/0x980 > > check_unmap from debug_dma_unmap_page+0x8c/0x9c > > debug_dma_unmap_page from moxart_mac_free_memory+0x3c/0xa8 > > moxart_mac_free_memory from moxart_mac_probe+0x190/0x218 > > moxart_mac_probe from platform_probe+0x48/0x88 > > platform_probe from really_probe+0xc0/0x2e4 > > > > Fixes: 6c821bd9edc9 ("net: Add MOXA ART SoCs ethernet driver") > > Signed-off-by: Sergei Antonov <saproj@gmail.com> > > This looks correct as it is: > > Reviewed-by: Andrew Lunn <andrew@lunn.ch> > > But i do wonder how it go into the situation: An error during moxart_mac_probe() does "goto init_fail;" which calls moxart_mac_free_memory(). And by that time, priv->rx_mapping[i] are all zero yet.
diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c index f11f1cb92025..edd1dab2ec43 100644 --- a/drivers/net/ethernet/moxa/moxart_ether.c +++ b/drivers/net/ethernet/moxa/moxart_ether.c @@ -77,8 +77,9 @@ static void moxart_mac_free_memory(struct net_device *ndev) int i; for (i = 0; i < RX_DESC_NUM; i++) - dma_unmap_single(&priv->pdev->dev, priv->rx_mapping[i], - priv->rx_buf_size, DMA_FROM_DEVICE); + if (priv->rx_mapping[i]) + dma_unmap_single(&priv->pdev->dev, priv->rx_mapping[i], + priv->rx_buf_size, DMA_FROM_DEVICE); if (priv->tx_desc_base) dma_free_coherent(&priv->pdev->dev,
It fixes a warning during error unwinding: WARNING: CPU: 0 PID: 1 at kernel/dma/debug.c:963 check_unmap+0x704/0x980 DMA-API: moxart-ethernet 92000000.mac: device driver tries to free DMA memory it has not allocated [device address=0x0000000000000000] [size=1600 bytes] CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0+ #60 Hardware name: Generic DT based system unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x34/0x44 dump_stack_lvl from __warn+0xbc/0x1f0 __warn from warn_slowpath_fmt+0x94/0xc8 warn_slowpath_fmt from check_unmap+0x704/0x980 check_unmap from debug_dma_unmap_page+0x8c/0x9c debug_dma_unmap_page from moxart_mac_free_memory+0x3c/0xa8 moxart_mac_free_memory from moxart_mac_probe+0x190/0x218 moxart_mac_probe from platform_probe+0x48/0x88 platform_probe from really_probe+0xc0/0x2e4 Fixes: 6c821bd9edc9 ("net: Add MOXA ART SoCs ethernet driver") Signed-off-by: Sergei Antonov <saproj@gmail.com> --- drivers/net/ethernet/moxa/moxart_ether.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)