Re: [PATCH net v2] ice: fix packet corruption due to extraneous page flip

[Jacob Keller <jacob.e.keller@intel.com>]

On 5/7/2026 7:37 PM, John Ousterhout wrote:
> Correct: this patch only applies to the ice driver before its conversion.
> 
> The patch applies to versions 6.18.27 and 6.12.86. I believe the bug
> may also be present in 6.6.137, but the code has a slightly different
> structure there (the function ice_put_rx_mbuf doesn't yet exist in
> that version) so the patch would need to be reworked a bit.
> 
> This situation isn't all that rare. It isn't a zero-length packet that
> triggers it; it seems to happen if a packet uses every available byte
> in a buffer, ending precisely at the end of the buffer. When this
> happens, the NIC seems to generate an extra zero-length "buffer". This
> happens quite frequently (thousands of times per second in some of my
> workloads).
> 
> What keeps corruption from happening constantly is that there is only
> a problem if the "other half" of the buffer page is still active when
> the 0-length buffer is received from the NIC. I suspect that with TCP
> this is pretty unlikely: packet buffers get recycled quickly. If the
> other half is not in use, then it doesn't matter whether the page gets
> "flipped" while processing the 0-length buffer. I ran into this
> problem because I was testing Homa under conditions that caused some
> packet buffers to stay alive for longer periods of time.
> 
> -John-
Right. So I think we need to make sure the patch is cc'd to stable.
Technically it doesn't strictly follow any of the 3 rules, but its
closest to 3 with a clarification that there is no upstream equivalent
due to the libeth Rx refactor.

Thanks,
Jake