Re: [PATCH net] net: ethernet: ti: icssg: guard PA stat lookups

[Simon Horman <horms@kernel.org>]

On Tue, Jun 16, 2026 at 04:35:34PM +0200, Philippe Schenker wrote:
> From: Philippe Schenker <philippe.schenker@impulsing.ch>
> 
> icssg_ndo_get_stats64() unconditionally calls emac_get_stat_by_name()
> with FW PA stat names regardless of whether the PA stats block is
> present on the hardware.  emac_get_stat_by_name() already guards the
> PA stats lookup with `if (emac->prueth->pa_stats)`; when that pointer
> is NULL the lookup falls through to netdev_err() and returns -EINVAL.
> Because ndo_get_stats64 is polled regularly by the networking stack
> this produces thousands of log entries of the form:
> 
>   icssg-prueth icssg1-eth end0: Invalid stats FW_RX_ERROR
> 
> A secondary consequence is that the int(-EINVAL) return value is
> implicitly widened to a near-ULLONG_MAX unsigned value when accumulated
> into the __u64 fields of rtnl_link_stats64, silently corrupting the
> rx_errors, rx_dropped and tx_dropped counters reported by `ip -s link`.
> 
> Every other PA-aware code path in the driver is already guarded with
> the same `if (emac->prueth->pa_stats)` check.  Apply the same guard
> here.
> 
> Fixes: 0d15a26b247d ("net: ti: icssg-prueth: Add ICSSG FW Stats")

nit: no blank line between tags

> 
> Signed-off-by: Philippe Schenker <philippe.schenker@impulsing.ch>
> 
> Cc: danishanwar@ti.com
> Cc: rogerq@kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: stable@vger.kernel.org

Reviewed-by: Simon Horman <horms@kernel.org>