Currently, tracing fentry/fexit program return value can be anything,
and these return values are actually ignored by trampoline codes.
Let us force return value to be 0 to avoid confusion and allow
possible future extension. Patch #1 is the kernel change and
Patch #2 fixed the selftest.
Changelog:
v1 -> v2:
- explicitly specify expected return value ranges for all
attach types of the tracing programs. Any unspecified attach
type will return an error. This will force any future
tracing attach_type to be explicit about its return value
range (Andrii).
Yonghong Song (2):
bpf: enforce returning 0 for fentry/fexit progs
selftests/bpf: enforce returning 0 for fentry/fexit programs
kernel/bpf/verifier.c | 18 ++++++++++++++++++
.../selftests/bpf/progs/test_overhead.c | 4 ++--
2 files changed, 20 insertions(+), 2 deletions(-)
--
2.24.1
