[PATCH] bpftool: fix control flow graph segfault during edge creation

[Christoph Werle]

If the last instruction of a control flow graph building block is a
BPF_CALL, an incorrect edge with e->dst set to NULL is created and
results in a segfault during graph output.

Ensure that BPF_CALL as last instruction of a building block is handled
correctly and only generates a single edge unlike actual BPF_JUMP*
instructions.

Signed-off-by: Christoph Werle <christoph.werle@xxxxxxxxxx>
---
 tools/bpf/bpftool/cfg.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/bpf/bpftool/cfg.c b/tools/bpf/bpftool/cfg.c
index eec437cca2ea..e3785f9a697d 100644
--- a/tools/bpf/bpftool/cfg.c
+++ b/tools/bpf/bpftool/cfg.c
@@ -302,6 +302,7 @@ static bool func_add_bb_edges(struct func_node *func)
 
 		insn = bb->tail;
 		if (!is_jmp_insn(insn->code) ||
+		    BPF_OP(insn->code) == BPF_CALL ||
 		    BPF_OP(insn->code) == BPF_EXIT) {
 			e->dst = bb_next(bb);
 			e->flags |= EDGE_FLAG_FALLTHROUGH;
-- 
2.43.0