5.15 Kernel build error

[Grommish]

I'm working with the Octeon branch, which currently seems to suffer a nasty memleak under 5.10. It was suggested to see if maybe 5.15 didn't include a fix for it.

That being said, I've started the process of getting it to build, and managed to solve all the issues I've run into except one.

mips64-openwrt-linux-musl-ld: lib/kobject_uevent.o: in function `broadcast_uevent':
/home/grommish/openwrt/build_dir/target-mips64_octeonplus_64_musl/linux-octeon/linux-5.15.1/lib/kobject_uevent.c:724: undefined reference to `kfree_skb'
make[4]: *** [Makefile:1183: vmlinux] Error 1

Looking into the file:

int broadcast_uevent(struct sk_buff *skb, __u32 pid, __u32 group,
                     gfp_t allocation)
{
        kfree_skb(skb);
        return 0;
}

However, kfree_skb is defined in ./include/linux/skbuff.h, which is called in kobject_uevent.c

void kfree_skb(struct sk_buff *skb);

What am I missing?

[Grommish]

This was a linker error because CONFIG_NET was turned off. Interesting to note that kfree_skb() is called whether CONFIG_NET is enable or not, even though its an ifeq call in the file.

Adding CONFIG_NET fixed the issue