On Mon, May 04, 2026 at 03:26:23PM +0300, Daniil Iskhakov wrote:
> For 82599, QBRC is a 36-bit clear-on-read counter, while
> QPRC is a 32-bit clear-on-read counter. ixgbe_read_stats_registers()
> accumulates QBRC in a 64-bit software counter and, when CRC stripping
> is disabled, subtracts the CRC bytes accounted for each received packet.
>
> The CRC adjustment is computed as:
>
> delta_qprc * RTE_ETHER_CRC_LEN
>
> Since delta_qprc is 32-bit, the multiplication is performed in 32 bits
> and may wrap before the result is subtracted from the 64-bit QBRC
> accumulator. A full 32-bit packet delta needs more than 32 bits to
> represent the CRC-byte adjustment.
>
> Cast delta_qprc to uint64_t before the multiplication so the adjustment
> is computed with the same effective width as the byte counter.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: c03fcee9abbd ("ixgbe: remove CRC size from byte counters")
> Cc: [email protected]
>
> Signed-off-by: Daniil Iskhakov <[email protected]>
> ---
Acked-by: Bruce Richardson <[email protected]>
Applied to dpdk-next-net-intel.
Thanks,
/Bruce
