On Sat, Mar 05, 2022 at 01:20:42PM -0800, Yonghong Song wrote:
>
> On 3/4/22 11:16 AM, Hao Luo wrote:
> > Add test for percpu btf_type_tag. Similar to the "user" tag, we test
> > the following cases:
> >
> > 1. __percpu struct field.
> > 2. __percpu as function parameter.
> > 3. per_cpu_ptr() accepts dynamically allocated __percpu memory.
> >
> > Because the test for "user" and the test for "percpu" are very similar,
> > a little bit of refactoring has been done in btf_tag.c. Basically, both
> > tests share the same function for loading vmlinux and module btf.
> >
> > Example output from log:
> >
> > > ./test_progs -v -t btf_tag
> >
> > libbpf: prog 'test_percpu1': BPF program load failed: Permission denied
> > libbpf: prog 'test_percpu1': -- BEGIN PROG LOAD LOG --
> > ...
> > ; g = arg->a;
> > 1: (61) r1 = *(u32 *)(r1 +0)
> > R1 is ptr_bpf_testmod_btf_type_tag_1 access percpu memory: off=0
> > ...
> > test_btf_type_tag_mod_percpu:PASS:btf_type_tag_percpu 0 nsec
> > #26/6 btf_tag/btf_type_tag_percpu_mod1:OK
> >
> > libbpf: prog 'test_percpu2': BPF program load failed: Permission denied
> > libbpf: prog 'test_percpu2': -- BEGIN PROG LOAD LOG --
> > ...
> > ; g = arg->p->a;
> > 2: (61) r1 = *(u32 *)(r1 +0)
> > R1 is ptr_bpf_testmod_btf_type_tag_1 access percpu memory: off=0
> > ...
> > test_btf_type_tag_mod_percpu:PASS:btf_type_tag_percpu 0 nsec
> > #26/7 btf_tag/btf_type_tag_percpu_mod2:OK
> >
> > libbpf: prog 'test_percpu_load': BPF program load failed: Permission denied
> > libbpf: prog 'test_percpu_load': -- BEGIN PROG LOAD LOG --
> > ...
> > ; g = (__u64)cgrp->rstat_cpu->updated_children;
> > 2: (79) r1 = *(u64 *)(r1 +48)
> > R1 is ptr_cgroup_rstat_cpu access percpu memory: off=48
> > ...
> > test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu_load 0 nsec
> > #26/8 btf_tag/btf_type_tag_percpu_vmlinux_load:OK
> >
> > load_btfs:PASS:could not load vmlinux BTF 0 nsec
> > test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu 0 nsec
> > test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu_helper 0 nsec
> > #26/9 btf_tag/btf_type_tag_percpu_vmlinux_helper:OK
> >
> > Signed-off-by: Hao Luo <haoluo@xxxxxxxxxx>
>
> With one nit below.
>
> Acked-by: Yonghong Song <yhs@xxxxxx>
>
> > ---
> > .../selftests/bpf/bpf_testmod/bpf_testmod.c | 17 ++
> > .../selftests/bpf/prog_tests/btf_tag.c | 164 ++++++++++++++----
> > .../selftests/bpf/progs/btf_type_tag_percpu.c | 66 +++++++
> > 3 files changed, 218 insertions(+), 29 deletions(-)
> > create mode 100644 tools/testing/selftests/bpf/progs/btf_type_tag_percpu.c
> >
> > diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> > index 27d63be47b95..17c211f3b924 100644
> > --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> > +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> > @@ -33,6 +33,10 @@ struct bpf_testmod_btf_type_tag_2 {
> > struct bpf_testmod_btf_type_tag_1 __user *p;
> > };
> > +struct bpf_testmod_btf_type_tag_3 {
> > + struct bpf_testmod_btf_type_tag_1 __percpu *p;
> > +};
> > +
> > noinline int
> > bpf_testmod_test_btf_type_tag_user_1(struct bpf_testmod_btf_type_tag_1 __user *arg) {
> > BTF_TYPE_EMIT(func_proto_typedef);
> > @@ -46,6 +50,19 @@ bpf_testmod_test_btf_type_tag_user_2(struct bpf_testmod_btf_type_tag_2 *arg) {
> > return arg->p->a;
> > }
> > +noinline int
> > +bpf_testmod_test_btf_type_tag_percpu_1(struct bpf_testmod_btf_type_tag_1 __percpu *arg) {
> > + BTF_TYPE_EMIT(func_proto_typedef);
> > + BTF_TYPE_EMIT(func_proto_typedef_nested1);
> > + BTF_TYPE_EMIT(func_proto_typedef_nested2);
>
> Are these necessary? They have been defined in
> bpf_testmod_test_btf_type_tag_user_1().
Yonghong,
Thanks. Good catch. I've removed those while applying.
Hao,
Great work.
I really liked how patch 3 discovers MEM_PERCPU flag from
two sources: percpu_datasec and clang tag.
