On Thu, Nov 26, 2020 at 3:19 AM Marco Elver <elver@xxxxxxxxxx> wrote: > > On Wed, 25 Nov 2020 at 21:43, Jakub Kicinski <kuba@xxxxxxxxxx> wrote: > > > > On Wed, 25 Nov 2020 18:34:36 +0100 Marco Elver wrote: > > > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > > > index ffe3dcc0ebea..070b1077d976 100644 > > > --- a/net/core/skbuff.c > > > +++ b/net/core/skbuff.c > > > @@ -233,6 +233,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, > > > skb->end = skb->tail + size; > > > skb->mac_header = (typeof(skb->mac_header))~0U; > > > skb->transport_header = (typeof(skb->transport_header))~0U; > > > + skb_set_kcov_handle(skb, kcov_common_handle()); > > > > > > /* make sure we initialize shinfo sequentially */ > > > shinfo = skb_shinfo(skb); > > > @@ -249,9 +250,6 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, > > > > > > fclones->skb2.fclone = SKB_FCLONE_CLONE; > > > } > > > - > > > - skb_set_kcov_handle(skb, kcov_common_handle()); > > > > Why the move? > > v2 of the original series had it above. I frankly don't mind. > > 1. Group it with the other fields above? > > 2. Leave it at the end here? > > > > out: > > > return skb; > > > nodata: > > > @@ -285,8 +283,6 @@ static struct sk_buff *__build_skb_around(struct sk_buff *skb, > > > memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); > > > atomic_set(&shinfo->dataref, 1); > > > > > > - skb_set_kcov_handle(skb, kcov_common_handle()); > > > - > > > return skb; > > > } > > > > And why are we dropping this? > > It wasn't here originally. > > > If this was omitted in earlier versions it's just a independent bug, > > I don't think build_skb() will call __alloc_skb(), so we need a to > > set the handle here. > > Correct, that was an original omission. > > Will send v2. Does it make more sense to revert the patch that added the extensions and the follow-on fixes and add a separate new patch instead? If adding a new field to the skb, even if only in debug builds, please check with pahole how it affects struct layout if you haven't yet. The skb_extensions idea was mine. Apologies for steering this into an apparently unsuccessful direction. Adding new fields to skb is very rare because possibly problematic wrt allocation.
