With current-ish Linus 2.6 BK, I'm seeing this: net/ipv4/netfilter/ipt_hashlimit.c:96: warning: type defaults to `int' in declaration of `DECLARE_LOCK' net/ipv4/netfilter/ipt_hashlimit.c:96: warning: parameter names (without types) in function declaration net/ipv4/netfilter/ipt_hashlimit.c: In function `htable_create': net/ipv4/netfilter/ipt_hashlimit.c:237: warning: implicit declaration of function `LOCK_BH' net/ipv4/netfilter/ipt_hashlimit.c:237: error: `hashlimit_lock' undeclared (first use in this function) net/ipv4/netfilter/ipt_hashlimit.c:237: error: (Each undeclared identifier is reported only once/home/rmk/bk/linux-2.6-rmk/net/ipv4/netfilter/ipt_hashlimit.c:237: error: for each function it appears in.) net/ipv4/netfilter/ipt_hashlimit.c:239: warning: implicit declaration of function `UNLOCK_BH' net/ipv4/netfilter/ipt_hashlimit.c: In function `htable_find_get': net/ipv4/netfilter/ipt_hashlimit.c:305: error: `hashlimit_lock' undeclared (first use in this function) net/ipv4/netfilter/ipt_hashlimit.c: In function `htable_put': net/ipv4/netfilter/ipt_hashlimit.c:321: error: `hashlimit_lock' undeclared (first use in this function) net/ipv4/netfilter/ipt_hashlimit.c: At top level: net/ipv4/netfilter/ipt_hashlimit.c:96: warning: `DECLARE_LOCK' declared `static' but never defined Looks like ipt_hashlimit.c is missing an include? -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core