Hi,
So this is the fix for the bug that actually prevented me to integrate HID-BPF in v6.2.
While testing the code base with LLVM, I realized that clang was smarter than I expected it to be, and it sometimes inlined a function or not depending on the branch. This lead to segfaults because my current code in linux-next is messing up the bpf programs refcounts assuming that I had enough observability over the kernel.
So I came back to the drawing board and realized that what I was missing was exactly a bpf_link, to represent the attachment of a bpf program to a HID device. This is the bulk of the series, in patch 6/9.
The other patches are cleanups, tests, and also the addition of the vmtests.sh script I run locally, largely inspired by the one in the bpf selftests dir. This allows very fast development of HID-BPF, assuming we have tests that cover the bugs :)
Cheers, Benjamin
Benjamin Tissoires (9): selftests: hid: add vmtest.sh selftests: hid: allow to compile hid_bpf with LLVM selftests: hid: attach/detach 2 bpf programs, not just one selftests: hid: ensure the program is correctly pinned selftests: hid: prepare tests for HID_BPF API change HID: bpf: rework how programs are attached and stored in the kernel selftests: hid: enforce new attach API HID: bpf: clean up entrypoint HID: bpf: reorder BPF registration
Documentation/hid/hid-bpf.rst | 12 +- drivers/hid/bpf/entrypoints/entrypoints.bpf.c | 9 - .../hid/bpf/entrypoints/entrypoints.lskel.h | 188 ++++-------- drivers/hid/bpf/hid_bpf_dispatch.c | 28 +- drivers/hid/bpf/hid_bpf_dispatch.h | 3 - drivers/hid/bpf/hid_bpf_jmp_table.c | 116 +++---- include/linux/hid_bpf.h | 7 + tools/testing/selftests/hid/.gitignore | 1 + tools/testing/selftests/hid/Makefile | 10 +- tools/testing/selftests/hid/config.common | 241 +++++++++++++++ tools/testing/selftests/hid/config.x86_64 | 4 + tools/testing/selftests/hid/hid_bpf.c | 32 +- tools/testing/selftests/hid/progs/hid.c | 13 + tools/testing/selftests/hid/vmtest.sh | 284 ++++++++++++++++++ 14 files changed, 724 insertions(+), 224 deletions(-) create mode 100644 tools/testing/selftests/hid/config.common create mode 100644 tools/testing/selftests/hid/config.x86_64 create mode 100755 tools/testing/selftests/hid/vmtest.sh