Commit a5f6b9d5 authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'Enable struct_ops programs to be sleepable' 

David Vernet says:

====================

This is part 4 of https://lore.kernel.org/bpf/20230123232228.646563-1-void@manifault.com/

Part 3: https://lore.kernel.org/all/20230125050359.339273-1-void@manifault.com/
Part 2: https://lore.kernel.org/all/20230124160802.1122124-1-void@manifault.com/



Changelog:
----------
v3 -> v4:
- Fix accidental typo in name of dummy_st_ops introduced in v2, moving
  it back to dummy_st_ops from dummy_st_ops_success. Should fix s390x
  testruns.

v2 -> v3:
- Don't call a KF_SLEEPABLE kfunc from the dummy_st_ops testsuite, and
  remove the newly added bpf_kfunc_call_test_sleepable() test kfunc
  (Martin).
- Include vmlinux.h from progs/dummy_st_ops_success.c (previously
  progs/dummy_st_ops.c) rather than manually defining
  struct bpf_dummy_ops_state and struct bpf_dummy_ops.
  (Martin).
- Fix a typo added to prog_tests/dummy_st_ops.c in a previous version:
  s/trace_dummy_st_ops_success__open/trace_dummy_st_ops__open.

v1 -> v2:
- Add support for specifying sleepable struct_ops programs with
  struct_ops.s in libbpf (Alexei).
- Move failure test case into new dummy_st_ops_fail.c prog file.
- Update test_dummy_sleepable() to use struct_ops.s instead of manually
  setting prog flags. Also remove open_load_skel() helper which is no
  longer needed.
- Fix verifier tests to expect new sleepable prog failure message.
====================

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 2514a312 7dd88059

include/linux/bpf.h

+3 −1
Original line number Diff line number Diff line
@@ -1422,7 +1422,8 @@ struct bpf_struct_ops { 
	const struct bpf_verifier_ops *verifier_ops;

	int (*init)(struct btf *btf);

	int (*check_member)(const struct btf_type *t,

			    const struct btf_member *member);

			    const struct btf_member *member,

			    const struct bpf_prog *prog);

	int (*init_member)(const struct btf_type *t,

			   const struct btf_member *member,

			   void *kdata, const void *udata);
@@ -1473,6 +1474,7 @@ struct bpf_dummy_ops { 
	int (*test_1)(struct bpf_dummy_ops_state *cb);

	int (*test_2)(struct bpf_dummy_ops_state *cb, int a1, unsigned short a2,

		      char a3, unsigned long a4);

	int (*test_sleepable)(struct bpf_dummy_ops_state *cb);

};



int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr,

kernel/bpf/verifier.c

+4 −3
Original line number Diff line number Diff line
@@ -16792,7 +16792,7 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) 
	}



	if (st_ops->check_member) {

		int err = st_ops->check_member(t, member);

		int err = st_ops->check_member(t, member, prog);



		if (err) {

			verbose(env, "attach to unsupported member %s of struct %s\n",
@@ -17114,7 +17114,8 @@ static bool can_be_sleepable(struct bpf_prog *prog) 
		}

	}

	return prog->type == BPF_PROG_TYPE_LSM ||

	       prog->type == BPF_PROG_TYPE_KPROBE; /* only for uprobes */

	       prog->type == BPF_PROG_TYPE_KPROBE /* only for uprobes */ ||

	       prog->type == BPF_PROG_TYPE_STRUCT_OPS;

}



static int check_attach_btf_id(struct bpf_verifier_env *env)
@@ -17136,7 +17137,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) 
	}



	if (prog->aux->sleepable && !can_be_sleepable(prog)) {

		verbose(env, "Only fentry/fexit/fmod_ret, lsm, iter and uprobe programs can be sleepable\n");

		verbose(env, "Only fentry/fexit/fmod_ret, lsm, iter, uprobe, and struct_ops programs can be sleepable\n");

		return -EINVAL;

	}

net/bpf/bpf_dummy_struct_ops.c

+18 −0
Original line number Diff line number Diff line
@@ -154,6 +154,23 @@ static bool bpf_dummy_ops_is_valid_access(int off, int size, 
	return bpf_tracing_btf_ctx_access(off, size, type, prog, info);

}



static int bpf_dummy_ops_check_member(const struct btf_type *t,

				      const struct btf_member *member,

				      const struct bpf_prog *prog)

{

	u32 moff = __btf_member_bit_offset(t, member) / 8;



	switch (moff) {

	case offsetof(struct bpf_dummy_ops, test_sleepable):

		break;

	default:

		if (prog->aux->sleepable)

			return -EINVAL;

	}



	return 0;

}



static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log,

					   const struct bpf_reg_state *reg,

					   int off, int size, enum bpf_access_type atype,
@@ -208,6 +225,7 @@ static void bpf_dummy_unreg(void *kdata) 
struct bpf_struct_ops bpf_bpf_dummy_ops = {

	.verifier_ops = &bpf_dummy_verifier_ops,

	.init = bpf_dummy_init,

	.check_member = bpf_dummy_ops_check_member,

	.init_member = bpf_dummy_init_member,

	.reg = bpf_dummy_reg,

	.unreg = bpf_dummy_unreg,

net/ipv4/bpf_tcp_ca.c

+2 −1
Original line number Diff line number Diff line
@@ -248,7 +248,8 @@ static int bpf_tcp_ca_init_member(const struct btf_type *t, 
}



static int bpf_tcp_ca_check_member(const struct btf_type *t,

				   const struct btf_member *member)

				   const struct btf_member *member,

				   const struct bpf_prog *prog)

{

	if (is_unsupported(__btf_member_bit_offset(t, member) / 8))

		return -ENOTSUPP;

tools/lib/bpf/libbpf.c

+1 −0
Original line number Diff line number Diff line
@@ -8605,6 +8605,7 @@ static const struct bpf_sec_def section_defs[] = { 
	SEC_DEF("cgroup/setsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE),

	SEC_DEF("cgroup/dev",		CGROUP_DEVICE, BPF_CGROUP_DEVICE, SEC_ATTACHABLE_OPT),

	SEC_DEF("struct_ops+",		STRUCT_OPS, 0, SEC_NONE),

	SEC_DEF("struct_ops.s+",	STRUCT_OPS, 0, SEC_SLEEPABLE),

	SEC_DEF("sk_lookup",		SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE),

};