Re: [PATCH net-next v2 3/3] net: devmem: decode DMA addresses for TX

[Paolo Abeni <pabeni@redhat.com>]

On 9/29/26 11:43, Paolo Abeni wrote:
> On 9/25/26 22:15, Stanislav Fomichev wrote:
>> On 32-bit architectures where dma_addr_t is wider than unsigned long,
>> page_pool_set_dma_addr_netmem() stores page-aligned DMA addresses shifted
>> by PAGE_SHIFT. The net_iov branch of __skb_frag_dma_map() adds byte offsets
>> to the encoded value, so the NIC is programmed with an invalid DMA address.
>> This can trigger an IOMMU fault or DMA from unintended memory.
>>
>> Consolidate DMA address encoding, decoding, and representability checks in
>> netmem helpers. Use the common decoder from the page pool and net_iov TX
>> paths so both interpret stored addresses consistently.
>>
>> Fixes: bd61848900bf ("net: devmem: Implement TX path")
>> Reviewed-by: Mina Almasry <almasrymina@google.com>
>> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
> Fixes tag for net-next patches pointing to old code are highly discouraged.
> My understanding is that netem on 32 bits is mostly a theoretical thing,
> i.e. no actual usage.
> Would you be ok to strip the tag? No need to repost, just reply here.
Actually the above is more FYI than a real request. I'll apply the
series stripping the tag.

/P