Re: [PATCH net] net: skbuff: fix missing zerocopy reference in pskb_carve helpers

[lazyming]

I reviewed the Sashiko AI review of this patch and it raised two
issues worth noting:

1. Stale shinfo after skb_orphan_frags (vhost_net path) -- this can
   lead to UAF when skb_zcopy_clear() fires on a destructor_arg that
   was already freed by skb_copy_ubufs().

2. SKBFL_MANAGED_FRAG_REFS page ref leak (io_uring path) -- page refs
   from skb_frag_ref() are never released because skb_release_data()
   skips __skb_frag_unref() when MANAGED_FRAG_REFS is set.

Both are pre-existing bugs in the carve helpers, not introduced by
this patch. This patch only fixes the missing net_zcopy_get() for the
MSG_ZEROCOPY TCP path (SKBFL_ZEROCOPY_ENABLE without SKBFL_SHARED_FRAG),
which is unrelated to either issue above.

Could you re-review this patch? Issue 1 in particular looks genuinely
dangerous and probably deserves a separate fix from someone familiar
with the vhost_net zcopy path.