__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> --- net/dsa/tag_ksz.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c index 945a9bd5ba35..8ef2085349e7 100644 --- a/net/dsa/tag_ksz.c +++ b/net/dsa/tag_ksz.c @@ -24,7 +24,7 @@ static struct sk_buff *ksz_common_xmit(struct sk_buff *skb, if (skb_tailroom(skb) >= padlen + len) { /* Let dsa_slave_xmit() free skb */ - if (__skb_put_padto(skb, skb->len + padlen, false)) + if (__skb_put_padto(skb, ETH_ZLEN + len, false)) return NULL; nskb = skb; @@ -45,7 +45,7 @@ static struct sk_buff *ksz_common_xmit(struct sk_buff *skb, /* Let skb_put_padto() free nskb, and let dsa_slave_xmit() free * skb */ - if (skb_put_padto(nskb, nskb->len + padlen)) + if (skb_put_padto(nskb, ETH_ZLEN + len)) return NULL; consume_skb(skb); -- Christian Eggers Embedded software developer Arnold & Richter Cine Technik GmbH & Co. Betriebs KG Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918 Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477 Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler