Sasha,
This patch should not be applied to any of the stable kernels. It was reverted in f9dabe016b63 ("bpf: Undo off-by-one in interpreter tail call count limit").
I don't think it will pass the CI selftests so maybe it wouldn't be applied anyway, but nevertheless I want to inform you about it.
Johan
On Thu, Sep 9, 2021 at 1:43 PM Sasha Levin sashal@kernel.org wrote:
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@anyfinetw... 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