[PATCH net v6 0/4] octeon_ep, octeon_ep_vf: fix RX skb frags overflow and page leak

[Maoyi Xie]

The octeon_ep and octeon_ep_vf RX paths add one skb fragment per buffer
with no bound against MAX_SKB_FRAGS. buff_info->len comes from the device
response header. A long packet needs about 18 fragments. That is one past
the default MAX_SKB_FRAGS of 17. skb_add_rx_frag() then writes past
shinfo->frags[]. Patch 2 bounds octeon_ep. Patch 4 bounds octeon_ep_vf.

Both drivers also leak the pages of a dropped multi-buffer packet. The
drop path unmaps each buffer but never frees its page. Patch 1 fixes
octeon_ep. Patch 3 is Guangshuo Li's fix for octeon_ep_vf. The overflow
drops in patch 2 and patch 4 reuse those helpers. They free their pages
too.

The drop drain length derives from the device length. It had no bound
against the ring. Patch 1 and patch 4 stop the drain after MAX_SKB_FRAGS
fragments. A valid packet never holds more. This keeps a bad device length
from running the drain past the ring.

v6:
 - octeon_ep: add patch 1 to free the dropped RX buffer pages, per Jakub
   Kicinski. The drop path leaked the head page and every fragment page.
   The overflow drop in patch 2 reuses that helper. The v5 cover deferred
   this fix to a follow-up.
 - octeon_ep, octeon_ep_vf: bound the drop drain to MAX_SKB_FRAGS. The drain
   length derives from the device length. A bad length could run it past
   the ring. This is defense in depth against a misbehaving device.

v1: https://lore.kernel.org/r/20260701112825.1653044-1-maoyixie.tju@xxxxxxxxx
v2: https://lore.kernel.org/r/20260702180518.2013324-1-maoyixie.tju@xxxxxxxxx
v3: https://lore.kernel.org/r/20260704061511.2350737-1-maoyixie.tju@xxxxxxxxx
v4: https://lore.kernel.org/r/20260706150208.2944898-1-maoyixie.tju@xxxxxxxxx
v5: https://lore.kernel.org/r/20260716063432.2908100-1-maoyixie.tju@xxxxxxxxx

Guangshuo Li (1):
  octeon_ep_vf: Fix RX page leak on napi_build_skb() failure

Maoyi Xie (3):
  octeon_ep: free the dropped RX buffer pages
  octeon_ep: fix skb frags overflow in the RX path
  octeon_ep_vf: fix skb frags overflow in the RX path

 .../net/ethernet/marvell/octeon_ep/octep_rx.c | 19 ++++++-
 .../marvell/octeon_ep_vf/octep_vf_rx.c        | 52 +++++++++++++------
 2 files changed, 53 insertions(+), 18 deletions(-)

--
2.34.1