| Message ID | 5c4df4171225ab664c748da190c6f2c2f662c48b.1742557254.git.pabeni@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | udp_tunnel: GRO optimization follow-up | expand |
Paolo Abeni wrote: > Nathan reported that the compiler is not happy to use a zero > size udp_tunnel_gro_types array: > > net/ipv4/udp_offload.c:130:8: warning: array index 0 is past the end of the array (that has type 'struct udp_tunnel_type_entry[0]') [-Warray-bounds] > 130 | udp_tunnel_gro_types[0].gro_receive); > | ^ ~ > include/linux/static_call.h:154:42: note: expanded from macro 'static_call_update' > 154 | typeof(&STATIC_CALL_TRAMP(name)) __F = (func); \ > | ^~~~ > net/ipv4/udp_offload.c:47:1: note: array 'udp_tunnel_gro_types' declared here > 47 | static struct udp_tunnel_type_entry udp_tunnel_gro_types[UDP_MAX_TUNNEL_TYPES]; > | ^ > 1 warning generated. > > In such (unusual) configuration we should skip entirely the > static call optimization accounting. > > Reported-by: syzbot+8c469a2260132cd095c1@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/netdev/cover.1741718157.git.pabeni@redhat.com/T/#m6e309a49f04330de81a618c3c166368252ba42e4 > Fixes: 311b36574ceac ("udp_tunnel: use static call for GRO hooks when possible") > Signed-off-by: Paolo Abeni <pabeni@redhat.com> Should CONFIG_NET_UDP_TUNNEL just not be user selectable and only enabled by implementations of UDP tunnels like vxlan and geneve? > --- > net/ipv4/udp_offload.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c > index 02365b818f1af..fd2b8e3830beb 100644 > --- a/net/ipv4/udp_offload.c > +++ b/net/ipv4/udp_offload.c > @@ -83,7 +83,7 @@ void udp_tunnel_update_gro_rcv(struct sock *sk, bool add) > struct udp_sock *up = udp_sk(sk); > int i, old_gro_type_nr; > > - if (!up->gro_receive) > + if (!UDP_MAX_TUNNEL_TYPES || !up->gro_receive) > return; If that is too risky, I suppose this workaround is sufficient. But having a zero length array seems a bit odd.
2025-03-21, 12:35:34 -0400, Willem de Bruijn wrote: > Paolo Abeni wrote: > > Nathan reported that the compiler is not happy to use a zero > > size udp_tunnel_gro_types array: > > > > net/ipv4/udp_offload.c:130:8: warning: array index 0 is past the end of the array (that has type 'struct udp_tunnel_type_entry[0]') [-Warray-bounds] > > 130 | udp_tunnel_gro_types[0].gro_receive); > > | ^ ~ > > include/linux/static_call.h:154:42: note: expanded from macro 'static_call_update' > > 154 | typeof(&STATIC_CALL_TRAMP(name)) __F = (func); \ > > | ^~~~ > > net/ipv4/udp_offload.c:47:1: note: array 'udp_tunnel_gro_types' declared here > > 47 | static struct udp_tunnel_type_entry udp_tunnel_gro_types[UDP_MAX_TUNNEL_TYPES]; > > | ^ > > 1 warning generated. > > > > In such (unusual) configuration we should skip entirely the > > static call optimization accounting. > > > > Reported-by: syzbot+8c469a2260132cd095c1@syzkaller.appspotmail.com > > Closes: https://lore.kernel.org/netdev/cover.1741718157.git.pabeni@redhat.com/T/#m6e309a49f04330de81a618c3c166368252ba42e4 > > Fixes: 311b36574ceac ("udp_tunnel: use static call for GRO hooks when possible") > > Signed-off-by: Paolo Abeni <pabeni@redhat.com> > > Should CONFIG_NET_UDP_TUNNEL just not be user selectable and only > enabled by implementations of UDP tunnels like vxlan and geneve? It's already not user selectable? config NET_UDP_TUNNEL tristate (no string after bool/tristate, so no manual config) But there are tunnels that don't do GRO, so they're not counted in UDP_MAX_TUNNEL_TYPES, and if only those types are enabled, we'll have CONFIG_NET_UDP_TUNNEL=y with UDP_MAX_TUNNEL_TYPES == 0. > > --- > > net/ipv4/udp_offload.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c > > index 02365b818f1af..fd2b8e3830beb 100644 > > --- a/net/ipv4/udp_offload.c > > +++ b/net/ipv4/udp_offload.c > > @@ -83,7 +83,7 @@ void udp_tunnel_update_gro_rcv(struct sock *sk, bool add) > > struct udp_sock *up = udp_sk(sk); > > int i, old_gro_type_nr; > > > > - if (!up->gro_receive) > > + if (!UDP_MAX_TUNNEL_TYPES || !up->gro_receive) > > return; > > If that is too risky, I suppose this workaround is sufficient. > But having a zero length array seems a bit odd. I think the alternative would be to add #if UDP_MAX_TUNNEL_TYPES > 0 around some of this code.
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 02365b818f1af..fd2b8e3830beb 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -83,7 +83,7 @@ void udp_tunnel_update_gro_rcv(struct sock *sk, bool add) struct udp_sock *up = udp_sk(sk); int i, old_gro_type_nr; - if (!up->gro_receive) + if (!UDP_MAX_TUNNEL_TYPES || !up->gro_receive) return; mutex_lock(&udp_tunnel_gro_type_lock);
Nathan reported that the compiler is not happy to use a zero size udp_tunnel_gro_types array: net/ipv4/udp_offload.c:130:8: warning: array index 0 is past the end of the array (that has type 'struct udp_tunnel_type_entry[0]') [-Warray-bounds] 130 | udp_tunnel_gro_types[0].gro_receive); | ^ ~ include/linux/static_call.h:154:42: note: expanded from macro 'static_call_update' 154 | typeof(&STATIC_CALL_TRAMP(name)) __F = (func); \ | ^~~~ net/ipv4/udp_offload.c:47:1: note: array 'udp_tunnel_gro_types' declared here 47 | static struct udp_tunnel_type_entry udp_tunnel_gro_types[UDP_MAX_TUNNEL_TYPES]; | ^ 1 warning generated. In such (unusual) configuration we should skip entirely the static call optimization accounting. Reported-by: syzbot+8c469a2260132cd095c1@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/cover.1741718157.git.pabeni@redhat.com/T/#m6e309a49f04330de81a618c3c166368252ba42e4 Fixes: 311b36574ceac ("udp_tunnel: use static call for GRO hooks when possible") Signed-off-by: Paolo Abeni <pabeni@redhat.com> --- net/ipv4/udp_offload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)