Re: [PATCH net-next v6 0/4] net: stmmac: fix DMA descriptor ring cleanup issues

[Paolo Abeni]

On 10/24/26 09:13, Ding Hui wrote:
> From: Ding Hui <dinghui@xxxxxxxxxxx>
>
> Hello,
>
> This series fixes the NULL pointer dereferences in the stmmac TX/RX
> DMA resource cleanup paths and the associated error path issues,
> found on a DWMAC platform whose descriptor ring allocation may fail
> under memory pressure.
>
> Patch 1 adds NULL guards in the free helpers and makes them clear
> the pointers they free, so that a NULL pointer reliably means "not
> allocated" for the long-lived priv->dma_conf.
>
> Patch 2 makes the per-queue allocation functions undo their own
> allocations on error, instead of leaving the cleanup to the outer
> error paths that would then walk partially-initialized queues.
>
> Patch 3 releases the descriptor resources through priv->dma_conf
> when __stmmac_open() fails after copying the temporary dma_conf, so
> the long-lived configuration stays consistent with the resource
> cleanup.
>
> Patch 4 holds RTNL around the descriptors_status debugfs reader and
> skips queues whose rings are not allocated.
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