bpf: Consolidate sleepable checks in check_func_call()

The sleepable context check for global function calls in
check_func_call() open-codes the same checks that in_sleepable_context()
already performs. Replace the open-coded check with a call to
in_sleepable_context() and use non_sleepable_context_description() for
the error message, consistent with check_helper_call() and
check_kfunc_call().

Note that in_sleepable_context() also checks active_locks, which
overlaps with the existing active_locks check above it. However, the two
checks serve different purposes: the active_locks check rejects all
global function calls while holding a lock (not just sleepable ones), so
it must remain as a separate guard.

Update the expected error messages in the irq and preempt_lock selftests
to match.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260318174327.3151925-4-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 5 insertions, 6 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index a9130c4888f7..80a9eab79cac 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -210,6 +210,8 @@ static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env);
 static int ref_set_non_owning(struct bpf_verifier_env *env,
 			      struct bpf_reg_state *reg);
 static bool is_trusted_reg(const struct bpf_reg_state *reg);
+static inline bool in_sleepable_context(struct bpf_verifier_env *env);
+static const char *non_sleepable_context_description(struct bpf_verifier_env *env);
 
 static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux)
 {
@@ -10948,12 +10950,9 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
 			return -EINVAL;
 		}
 
-		if (env->subprog_info[subprog].might_sleep &&
-		    (env->cur_state->active_rcu_locks || env->cur_state->active_preempt_locks ||
-		     env->cur_state->active_irq_id || !in_sleepable(env))) {
-			verbose(env, "global functions that may sleep are not allowed in non-sleepable context,\n"
-				     "i.e., in a RCU/IRQ/preempt-disabled section, or in\n"
-				     "a non-sleepable BPF program context\n");
+		if (env->subprog_info[subprog].might_sleep && !in_sleepable_context(env)) {
+			verbose(env, "sleepable global function %s() called in %s\n",
+				sub_name, non_sleepable_context_description(env));
 			return -EINVAL;
 		}