[PATCH RFC bpf-next v2 01/10] bpf/verifier: introduce in_sleepable() helper

From: Benjamin Tissoires
Date: Wed Feb 14 2024 - 12:19:49 EST


No code change, but it'll allow to have only one place to change
everything when we add in_sleepable in cur_state.

Signed-off-by: Benjamin Tissoires <bentiss@xxxxxxxxxx>

---

changes in v2 (compared to the one attaches to v1 0/9):
- dropped the cur_state flag, so it can be put first
---
kernel/bpf/verifier.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 64fa188d00ad..7831adba9abf 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5255,6 +5255,11 @@ static int map_kptr_match_type(struct bpf_verifier_env *env,
return -EINVAL;
}

+static bool in_sleepable(struct bpf_verifier_env *env)
+{
+ return env->prog->aux->sleepable;
+}
+
/* The non-sleepable programs and sleepable programs with explicit bpf_rcu_read_lock()
* can dereference RCU protected pointers and result is PTR_TRUSTED.
*/
@@ -5262,7 +5267,7 @@ static bool in_rcu_cs(struct bpf_verifier_env *env)
{
return env->cur_state->active_rcu_lock ||
env->cur_state->active_lock.ptr ||
- !env->prog->aux->sleepable;
+ !in_sleepable(env);
}

/* Once GCC supports btf_type_tag the following mechanism will be replaced with tag check */
@@ -10149,7 +10154,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
return -EINVAL;
}

- if (!env->prog->aux->sleepable && fn->might_sleep) {
+ if (!in_sleepable(env) && fn->might_sleep) {
verbose(env, "helper call might sleep in a non-sleepable prog\n");
return -EINVAL;
}
@@ -10179,7 +10184,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
return -EINVAL;
}

- if (env->prog->aux->sleepable && is_storage_get_function(func_id))
+ if (in_sleepable(env) && is_storage_get_function(func_id))
env->insn_aux_data[insn_idx].storage_get_func_atomic = true;
}

@@ -11538,7 +11543,7 @@ static bool check_css_task_iter_allowlist(struct bpf_verifier_env *env)
return true;
fallthrough;
default:
- return env->prog->aux->sleepable;
+ return in_sleepable(env);
}
}

@@ -12059,7 +12064,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
}

sleepable = is_kfunc_sleepable(&meta);
- if (sleepable && !env->prog->aux->sleepable) {
+ if (sleepable && !in_sleepable(env)) {
verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name);
return -EACCES;
}
@@ -18197,7 +18202,7 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
return -E2BIG;
}

- if (env->prog->aux->sleepable)
+ if (in_sleepable(env))
atomic64_inc(&map->sleepable_refcnt);
/* hold the map. If the program is rejected by verifier,
* the map will be released by release_maps() or it
@@ -19673,7 +19678,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
}

if (is_storage_get_function(insn->imm)) {
- if (!env->prog->aux->sleepable ||
+ if (!in_sleepable(env) ||
env->insn_aux_data[i + delta].storage_get_func_atomic)
insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_ATOMIC);
else

--
2.43.0