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: Alexei Starovoitov <ast@kernel.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index bb38b01b738f..6bd097e0d45f 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -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;
 	}