Re: [PATCH] net/ixgbe: fix good octets CRC adjustment

[Bruce Richardson <bruce.richardson@intel.com>]

On Wed, May 06, 2026 at 05:17:04PM +0100, Bruce Richardson wrote:
> On Mon, May 04, 2026 at 05:15:24PM +0300, Daniil Iskhakov wrote:
> > On some devices, such as 82599, GORC is a 36-bit clear-on-read counter,
> > while GPRC is a 32-bit clear-on-read counter.
> > ixgbe_read_stats_registers() accumulates GORC in a 64-bit software
> > counter and, when CRC stripping is disabled, subtracts the CRC bytes
> > accounted for each received packet.
> > 
> > The driver does not read GPRC directly. Due to an erratum, it derives
> > the good packet delta from the sum of per-queue packet receives instead.
> > The 32-bit QPRC registers are used for this purpose.
> > 
> > delta_gprc is used as an accumulator for those per-queue deltas and is
> > then used to compute the CRC-byte adjustment. Keeping it 32-bit may wrap
> > the accumulated packet delta before it is used to adjust the 64-bit GORC
> > counter.
> > 
> > Make delta_gprc 64-bit so the accumulated packet delta and the CRC-byte
> > adjustment are computed without 32-bit overflow.
> > 
> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> > 
> > Fixes: c03fcee9abbd ("ixgbe: remove CRC size from byte counters")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Daniil Iskhakov <dish@amicon.ru>
> Acked-by: Bruce Richardson <bruce.richardson@intel.com>

Applied to dpdk-next-net-intel.
Thanks,
/Bruce