Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] netxen: TX fragment hardware limit bypass due to unstripped 0-length fragments --
commit daf1ad3622d94edcda5ee23317b335a0a1a7de23 Author: Josef Bacik <[email protected]> netxen: use pskb_may_pull() to pull excess TX frags into the head This commit replaces a direct call to __pskb_pull_tail() with pskb_may_pull() in the netxen driver's transmit path to pull excess fragments into the head. > diff --git a/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c > b/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c > index 67d9bf69f8f29..202deb64ddefb 100644 > --- a/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c > +++ b/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c > @@ -2045,7 +2045,7 @@ netxen_nic_xmit_frame(struct sk_buff *skb, struct > net_device *netdev) > delta += skb_frag_size(frag); > } > > - if (!__pskb_pull_tail(skb, delta)) > + if (!pskb_may_pull(skb, skb_headlen(skb) + delta)) [Severity: Medium] Does this change bypass the hardware limit for TX fragments by failing to strip 0-length fragments? If an SKB is transmitted with more than 14 fragments and the first excess fragments are 0-length, delta will be 0. The original code handled this by calling __pskb_pull_tail() which strips 0-length fragments even when the length to eat is 0: net/core/skbuff.c:__pskb_pull_tail() { ... int size = skb_frag_size(&skb_shinfo(skb)->frags[i]); if (size <= eat) { skb_frag_unref(skb, i); eat -= size; } else { ... } Because 0 <= 0 evaluates to true, the 0-length fragment is successfully removed and nr_frags is reduced. However, pskb_may_pull() returns true immediately without modifying the SKB when requested to pull skb_headlen(skb) + 0 bytes. This leaves the SKB with frag_count > NETXEN_MAX_FRAGS_PER_TX (14). Will the driver then program a descriptor chain with more fragments than the firmware supports? > goto drop_packet; > > frag_count = 1 + skb_shinfo(skb)->nr_frags; -- Sashiko AI review ยท https://sashiko.dev/#/patchset/20261007-b4-pskb-pull-tail-drivers-v1-0-9512b0fb9...@toxicpanda.com?part=7
