Introduce release_reg() to consolidate the release logic shared by both
helpers and kfuncs: dynptr release, kptr_xchg percpu-to-RCU conversion,
regular reference release, and NULL pass-through. NULL pass-through is
only allowed if the prototype indicates the argument may be null.
Determine release_regno from the function prototype/metadata before
argument checking, rather than discovering it dynamically during
argument processing. For helpers, scan the arg_type array in
check_func_proto() via check_proto_release_reg(). For kfuncs, set
release_regno to BPF_REG_1 in bpf_fetch_kfunc_arg_meta() when
KF_RELEASE is set. In the future when we start adding decl_tag to
kfunc arguments, we can just look at the function prototype instead
of a release_regno.
Extract ref_convert_alloc_rcu_protected() and
invalidate_rcu_protected_refs() to make it more clear what the code is
doing. For ref_convert_alloc_rcu_protected(), it pre-converts
MEM_ALLOC | MEM_PERCPU registers to MEM_RCU (clearing id so they
survive), then calls release_reference() to invalidate the remaining
registers and release the reference state.
Add KF_RELEASE to bpf_dynptr_file_discard() so its release_regno is set
via fetch_kfunc_meta rather than being assigned manually in the dynptr
argument processing. Set arg_type to ARG_PTR_TO_DYNPTR for
KF_ARG_PTR_TO_DYNPTR so that check_func_arg_reg_off() correctly allows
non-zero stack offsets for dynptr release arguments same as helper.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Link: https://lore.kernel.org/r/20260529014936.2811085-9-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce a set of BPF selftests to verify the safety and functionality
of wakeup_source kfuncs.
The suite includes:
1. A functional test (test_wakeup_source.c) that iterates over the
global wakeup_sources list. It uses CO-RE to read timing statistics
and validates them in user-space via the BPF ring buffer.
2. A negative test suite (wakeup_source_fail.c) ensuring the BPF
verifier correctly enforces reference tracking and type safety.
3. Enable CONFIG_PM_WAKELOCKS in the test config, allowing creation of
wakeup sources via /sys/power/wake_lock.
A shared header (wakeup_source.h) is introduced to ensure consistent
memory layout for the Ring Buffer data between BPF and user-space.
Signed-off-by: Samuel Wu <wusamuel@google.com>
Link: https://lore.kernel.org/r/20260511174559.659782-3-wusamuel@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
