[PATCH bpf-next] bpf, verifier: Correct tail_call_reachable for bpf prog

[Leon Hwang <hffilwlqm@gmail.com>]

It's confusing to inspect 'prog->aux->tail_call_reachable' with drgn[0],
when bpf prog has tail call but 'tail_call_reachable' is false.

This patch corrects 'tail_call_reachable' when bpf prog has tail call.

[0] https://github.com/osandov/drgn

Signed-off-by: Leon Hwang <hffilwlqm@gmail.com>
---
 kernel/bpf/verifier.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 81a3d2ced78d5..d7045676246a7 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2982,8 +2982,10 @@ static int check_subprogs(struct bpf_verifier_env *env)
 
 		if (code == (BPF_JMP | BPF_CALL) &&
 		    insn[i].src_reg == 0 &&
-		    insn[i].imm == BPF_FUNC_tail_call)
+		    insn[i].imm == BPF_FUNC_tail_call) {
 			subprog[cur_subprog].has_tail_call = true;
+			subprog[cur_subprog].tail_call_reachable = true;
+		}
 		if (BPF_CLASS(code) == BPF_LD &&
 		    (BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND))
 			subprog[cur_subprog].has_ld_abs = true;

base-commit: 2c6987105026a4395935a3db665c54eb1bafe782
-- 
2.44.0