[PATCH net] net: axienet: don't advance the TX ring head before the descriptor is ready

patchwork-bot+netdevbpf at kernel.org patchwork-bot+netdevbpf at kernel.org
Tue Oct 20 12:10:15 PDT 2026


Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba at kernel.org>:

On Tue, 13 Oct 2026 18:25:06 +0000 you wrote:
> axienet_start_xmit_dmaengine() bumps lp->tx_ring_head before
> skb_to_sgvec(), dma_map_sg() and device_prep_slave_sg(), and none of
> their error paths undo it.  The skb is freed and nothing is submitted,
> but the slot stays claimed.  axienet_dma_tx_cb() walks tx_ring_tail
> once per completion, so the next completion lands on the abandoned slot
> and dereferences whatever skb pointer is left there: NULL if the slot
> was never used or was already completed, or a stale skb that gets
> consumed a second time.  Every completion after that is accounted
> against the wrong slot.
> 
> [...]

Here is the summary with links:
  - [net] net: axienet: don't advance the TX ring head before the descriptor is ready
    https://git.kernel.org/netdev/net-next/c/cb790252f8e1

You are awesome, thank you!
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