David Ahern <dsah...@gmail.com> wrote: > $ make O=kbuild/perf -j 24 -s > In file included from /home/dsa/kernel-3.git/include/linux/kernel.h:10:0, > from /home/dsa/kernel-3.git/include/linux/list.h:9, > from /home/dsa/kernel-3.git/include/linux/module.h:9, > from /home/dsa/kernel-3.git/net/xfrm/xfrm_output.c:13: > /home/dsa/kernel-3.git/net/xfrm/xfrm_output.c: In function > ‘xfrm_output_resume’: > /home/dsa/kernel-3.git/include/linux/compiler.h:252:20: warning: array > subscript is above array bounds [-Warray-bounds] > __read_once_size(&(x), __u.__c, sizeof(x)); \ > ^~~~ > /home/dsa/kernel-3.git/include/linux/compiler.h:258:22: note: in > expansion of macro ‘__READ_ONCE’ > #define READ_ONCE(x) __READ_ONCE(x, 1) > ^~~~~~~~~~~ > /home/dsa/kernel-3.git/include/linux/rcupdate.h:350:48: note: in > expansion of macro ‘READ_ONCE’ > typeof(*p) *________p1 = (typeof(*p) *__force)READ_ONCE(p); \ > ^~~~~~~~~ > /home/dsa/kernel-3.git/include/linux/rcupdate.h:487:2: note: in > expansion of macro ‘__rcu_dereference_check’ > __rcu_dereference_check((p), (c) || rcu_read_lock_held(), __rcu) > ^~~~~~~~~~~~~~~~~~~~~~~ > /home/dsa/kernel-3.git/include/linux/rcupdate.h:545:28: note: in > expansion of macro ‘rcu_dereference_check’ > #define rcu_dereference(p) rcu_dereference_check(p, 0) > ^~~~~~~~~~~~~~~~~~~~~ > /home/dsa/kernel-3.git/include/linux/netfilter.h:218:15: note: in > expansion of macro ‘rcu_dereference’ > hook_head = rcu_dereference(net->nf.hooks_arp[hook]);
Hmpf. compiler can't know that this is only called for ipv4 and ipv6 families. > Line in question is the nf_hook in xfrm_output_resume. > NF_INET_POST_ROUTING = 4 which is greater than NF_ARP_NUMHOOKS = 3 > > I believe ef57170bbfdd6 is the commit that introduced the warning Yes. I will see how to best fix this, probably needs an explicit check on skb_dst(skb)->ops->family.
