Kernel Test Robot reported a compiler warning - a null pointer may be passed to memmove in __bpf_dynptr_{read,write} when building without networking support. The warning is correct from a static analysis standpoint, but not actually reachable. Without CONFIG_NET, creating dynptrs to skb metadata is impossible since the constructor kfunc is missing. Silence the false-postive diagnostic message by returning an error pointer from bpf_skb_meta_pointer stub when CONFIG_NET=n. Fixes: 6877cd392bae ("bpf: Enable read/write access to skb metadata through a dynptr") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202508212031.ir9b3B6Q-lkp@intel.com/ Suggested-by: Alexei Starovoitov Signed-off-by: Jakub Sitnicki --- Changes in v2: - Switch to an error pointer (Alexei) - Link to v1: https://lore.kernel.org/r/20250827-dynptr-skb-meta-no-net-v1-1-42695c402b16@cloudflare.com --- include/linux/filter.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 9092d8ea95c8..4241a885975f 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1816,7 +1816,7 @@ static inline void bpf_xdp_copy_buf(struct xdp_buff *xdp, unsigned long off, voi static inline void *bpf_skb_meta_pointer(struct sk_buff *skb, u32 offset) { - return NULL; + return ERR_PTR(-EOPNOTSUPP); } #endif /* CONFIG_NET */