From b61a28cf11d61f512172e673b8f8c4a6c789b425 Mon Sep 17 00:00:00 2001 From: Johan Almbladh Date: Wed, 28 Jul 2021 18:47:41 +0200 Subject: bpf: Fix off-by-one in tail call count limiting Before, the interpreter allowed up to MAX_TAIL_CALL_CNT + 1 tail calls. Now precisely MAX_TAIL_CALL_CNT is allowed, which is in line with the behavior of the x86 JITs. Signed-off-by: Johan Almbladh Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20210728164741.350370-1-johan.almbladh@anyfinetworks.com --- kernel/bpf/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index b1a5fc04492b..fe807b203a6f 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1562,7 +1562,7 @@ select_insn: if (unlikely(index >= array->map.max_entries)) goto out; - if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) + if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) goto out; tail_call_cnt++; -- cgit v1.2.3