Hi Benjamin, I love your patch! Yet something to improve: [auto build test ERROR on bpf-next/master] url: https://github.com/intel-lab-lkp/linux/commits/Benjamin-Tissoires/Introduce-eBPF-support-for-HID-devices/20220519-050506 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20220519/202205190720.TIuHyCp6-lkp@xxxxxxxxx/config) compiler: gcc-11 (Debian 11.2.0-20) 11.2.0 reproduce (this is a W=1 build): # https://github.com/intel-lab-lkp/linux/commit/ce32a9c683e801ac875c4e4eece32778040ed5cc git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Benjamin-Tissoires/Introduce-eBPF-support-for-HID-devices/20220519-050506 git checkout ce32a9c683e801ac875c4e4eece32778040ed5cc # save the config file mkdir build_dir && cp config build_dir/.config make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> All errors (new ones prefixed by >>): /usr/bin/ld: drivers/hid/hid-core.o: in function `hid_destroy_device': hid-core.c:(.text+0x10c0): undefined reference to `hid_bpf_destroy_device' /usr/bin/ld: drivers/hid/hid-core.o: in function `hid_allocate_device': hid-core.c:(.text+0x15c6): undefined reference to `hid_bpf_device_init' /usr/bin/ld: drivers/hid/hid-core.o: in function `hid_input_report': hid-core.c:(.text+0x22f7): undefined reference to `dispatch_hid_bpf_device_event' /usr/bin/ld: drivers/hid/hid-core.o: in function `hid_connect': >> hid-core.c:(.text+0x25da): undefined reference to `hid_bpf_connect_device' /usr/bin/ld: drivers/hid/hid-core.o: in function `hid_disconnect': >> hid-core.c:(.text+0xca1): undefined reference to `hid_bpf_disconnect_device' /usr/bin/ld: drivers/hid/hid-core.o: in function `hid_exit': hid-core.c:(.exit.text+0x7): undefined reference to `hid_bpf_ops' /usr/bin/ld: drivers/hid/hid-core.o: in function `hid_init': hid-core.c:(.init.text+0x35): undefined reference to `hid_bpf_ops' collect2: error: ld returned 1 exit status -- 0-DAY CI Kernel Test Service https://01.org/lkp