On Wed, Oct 14, 2020 at 07:47:50PM +0300, Vladimir Oltean wrote: > On Wed, Oct 14, 2020 at 06:17:19PM +0200, Christian Eggers wrote: > > __skb_put_padto() is called in order to ensure a minimal size of the > > sk_buff. The required minimal size is ETH_ZLEN + the size required for > > the tail tag. > > > > The current argument misses the size for the tail tag. The expression > > "skb->len + padlen" can be simplified to ETH_ZLEN. > > > > Too small sk_buffs typically result from cloning in > > dsa_skb_tx_timestamp(). The cloned sk_buff may not meet the minimum size > > requirements. > > > > Fixes: e71cb9e00922 ("net: dsa: ksz: fix skb freeing") > > Signed-off-by: Christian Eggers <cegg...@arri.de> > > --- > > Reviewed-by: Vladimir Oltean <olte...@gmail.com>
Actually no, I take that back. This statement: > The expression "skb->len + padlen" can be simplified to ETH_ZLEN. is false. skb->len + padlen == ETH_ZLEN only if skb->len is less than ETH_ZLEN. Otherwise, skb->len + padlen == skb->len. Otherwise said, the frame must be padded to max(skb->len, ETH_ZLEN) + tail tag length. So please keep the "skb->len + padlen + len". Thanks, -Vladimir