Re: [netfilter-nf-next:for-netdev-nf-next-26-06-14 3/11] net/netfilter/nf_conncount.c:502:18: sparse: sparse: incompatible types in comparison expression (different address spaces):

Re: [netfilter-nf-next:for-netdev-nf-next-26-06-14 3/11] net/netfilter/nf_conncount.c:502:18: sparse: sparse: incompatible types in comparison expression (different address spaces):

[Florian Westphal]

kernel test robot <lkp@intel.com> wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git for-netdev-nf-next-26-06-14
> head:   2354e975932dabb06fad239f07a3b68fd1809737
> commit: 64d7d5abe2160bba369b4a8f06bdf5630573bab0 [3/11] netfilter: nf_conncount: callers must hold rcu read lock
> config: x86_64-randconfig-123-20260614 (https://download.01.org/0day-ci/archive/20260615/202606150616.cpmJToWO-lkp@intel.com/config)
> compiler: gcc-13 (Debian 13.3.0-16) 13.3.0
> sparse: v0.6.5-rc1
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260615/202606150616.cpmJToWO-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202606150616.cpmJToWO-lkp@intel.com/
> 
> sparse warnings: (new ones prefixed by >>)
> >> net/netfilter/nf_conncount.c:502:18: sparse: sparse: incompatible types in comparison expression (different address spaces):
>    net/netfilter/nf_conncount.c:502:18: sparse:    struct rb_node [noderef] __rcu *
>    net/netfilter/nf_conncount.c:502:18: sparse:    struct rb_node *
>    net/netfilter/nf_conncount.c:510:34: sparse: sparse: incompatible types in comparison expression (different address spaces):
>    net/netfilter/nf_conncount.c:510:34: sparse:    struct rb_node [noderef] __rcu *
>    net/netfilter/nf_conncount.c:510:34: sparse:    struct rb_node *
>    net/netfilter/nf_conncount.c:512:34: sparse: sparse: incompatible types in comparison expression (different address spaces):
>    net/netfilter/nf_conncount.c:512:34: sparse:    struct rb_node [noderef] __rcu *
>    net/netfilter/nf_conncount.c:512:34: sparse:    struct rb_node *

Thanks but I have no intent to fix this.

Between rcu_dereference_raw() not giving sparse warnings but also not
providing any hints when callers don't hold rcu read lock and plain
rcu_dereference() that does give runtime coverage but results in above
sparse output I will pick the latter and just ignore these warnings.