[PATCH bpf-next 1/3] bpf: Consolidate sleepable checks in check_helper_call()

[Puranjay Mohan <puranjay@kernel.org>]

check_helper_call() prints the error message for every
env->cur_state->active* element when calling a sleepable helper.
Consolidate all of them into a single print statement.

The check for env->cur_state->active_locks was not part of the removed
print statements and will not be triggered with the consolidated print
as well because it is checked in do_check() before check_helper_call()
is even reached.

Acked-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
---
 kernel/bpf/verifier.c                         | 44 +++++++------------
 .../selftests/bpf/prog_tests/summarization.c  |  2 +-
 .../bpf/progs/verifier_async_cb_context.c     |  4 +-
 3 files changed, 20 insertions(+), 30 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 01c18f4268de..4e0f6be5d2d5 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11678,6 +11678,19 @@ static inline bool in_sleepable_context(struct bpf_verifier_env *env)
 	       in_sleepable(env);
 }
 
+static const char *non_sleepable_context_description(struct bpf_verifier_env *env)
+{
+	if (env->cur_state->active_rcu_locks)
+		return "rcu_read_lock region";
+	if (env->cur_state->active_preempt_locks)
+		return "non-preemptible region";
+	if (env->cur_state->active_irq_id)
+		return "IRQ-disabled region";
+	if (env->cur_state->active_locks)
+		return "lock region";
+	return "non-sleepable prog";
+}
+
 static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
 			     int *insn_idx_p)
 {
@@ -11717,11 +11730,6 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 		return -EINVAL;
 	}
 
-	if (!in_sleepable(env) && fn->might_sleep) {
-		verbose(env, "helper call might sleep in a non-sleepable prog\n");
-		return -EINVAL;
-	}
-
 	/* With LD_ABS/IND some JITs save/restore skb from r1. */
 	changes_data = bpf_helper_changes_pkt_data(func_id);
 	if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {
@@ -11738,28 +11746,10 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 		return err;
 	}
 
-	if (env->cur_state->active_rcu_locks) {
-		if (fn->might_sleep) {
-			verbose(env, "sleepable helper %s#%d in rcu_read_lock region\n",
-				func_id_name(func_id), func_id);
-			return -EINVAL;
-		}
-	}
-
-	if (env->cur_state->active_preempt_locks) {
-		if (fn->might_sleep) {
-			verbose(env, "sleepable helper %s#%d in non-preemptible region\n",
-				func_id_name(func_id), func_id);
-			return -EINVAL;
-		}
-	}
-
-	if (env->cur_state->active_irq_id) {
-		if (fn->might_sleep) {
-			verbose(env, "sleepable helper %s#%d in IRQ-disabled region\n",
-				func_id_name(func_id), func_id);
-			return -EINVAL;
-		}
+	if (fn->might_sleep && !in_sleepable_context(env)) {
+		verbose(env, "sleepable helper %s#%d in %s\n", func_id_name(func_id), func_id,
+			non_sleepable_context_description(env));
+		return -EINVAL;
 	}
 
 	/* Track non-sleepable context for helpers. */
diff --git a/tools/testing/selftests/bpf/prog_tests/summarization.c b/tools/testing/selftests/bpf/prog_tests/summarization.c
index 5dd6c120a838..6951786044ca 100644
--- a/tools/testing/selftests/bpf/prog_tests/summarization.c
+++ b/tools/testing/selftests/bpf/prog_tests/summarization.c
@@ -58,7 +58,7 @@ static void test_aux(const char *main_prog_name,
 	 * this particular combination can be enabled.
 	 */
 	if (!strcmp("might_sleep", replacement) && err) {
-		ASSERT_HAS_SUBSTR(log, "helper call might sleep in a non-sleepable prog", "error log");
+		ASSERT_HAS_SUBSTR(log, "sleepable helper bpf_copy_from_user#", "error log");
 		ASSERT_EQ(err, -EINVAL, "err");
 		test__skip();
 		goto out;
diff --git a/tools/testing/selftests/bpf/progs/verifier_async_cb_context.c b/tools/testing/selftests/bpf/progs/verifier_async_cb_context.c
index 39aff82549c9..6bf95550a024 100644
--- a/tools/testing/selftests/bpf/progs/verifier_async_cb_context.c
+++ b/tools/testing/selftests/bpf/progs/verifier_async_cb_context.c
@@ -31,7 +31,7 @@ static int timer_cb(void *map, int *key, struct bpf_timer *timer)
 }
 
 SEC("fentry/bpf_fentry_test1")
-__failure __msg("helper call might sleep in a non-sleepable prog")
+__failure __msg("sleepable helper bpf_copy_from_user#{{[0-9]+}} in non-sleepable prog")
 int timer_non_sleepable_prog(void *ctx)
 {
 	struct timer_elem *val;
@@ -47,7 +47,7 @@ int timer_non_sleepable_prog(void *ctx)
 }
 
 SEC("lsm.s/file_open")
-__failure __msg("helper call might sleep in a non-sleepable prog")
+__failure __msg("sleepable helper bpf_copy_from_user#{{[0-9]+}} in non-sleepable prog")
 int timer_sleepable_prog(void *ctx)
 {
 	struct timer_elem *val;
-- 
2.52.0