On 2023-08-29 12:09:15 +0200, Eric Dumazet wrote: > Another way to test this path for certain (without tcpdump having to race) > is to add a temporary/debug patch like this one: > > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index a298992060e6efdecb87c7ffc8290eafe330583f..20cc42be5e81cdca567515f2a886af4ada0fbe0a > 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -1749,7 +1749,8 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask) > int i, order, psize, new_frags; > u32 d_off; > > - if (skb_shared(skb) || skb_unclone(skb, gfp_mask)) > + if (skb_shared(skb) || > + pskb_expand_head(skb, 0, 0, gfp_mask)) > return -EINVAL; > > if (!num_frags) > > Note that this might catch other bugs :/ I was not able to make it allocate a new frags by running tcpdump while reproing the problem. However, I was able to do it with your patch.
