Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 5.14 101/252] bpf: Fix off-by-one in tail call count limiting | Date | Thu, 9 Sep 2021 07:38:35 -0400 |
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From: Johan Almbladh <johan.almbladh@anyfinetworks.com>
[ Upstream commit b61a28cf11d61f512172e673b8f8c4a6c789b425 ]
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 <johan.almbladh@anyfinetworks.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210728164741.350370-1-johan.almbladh@anyfinetworks.com Signed-off-by: Sasha Levin <sashal@kernel.org> --- kernel/bpf/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 0a28a8095d3e..82af6279992d 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1564,7 +1564,7 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *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++; -- 2.30.2
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