From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Johan Almbladh <johan.almbladh@anyfinetworks.com>,
Andrii Nakryiko <andrii@kernel.org>, Yonghong Song <yhs@fb.com>,
Sasha Levin <sashal@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH AUTOSEL 5.4 048/109] bpf: Fix off-by-one in tail call count limiting
Date: Thu, 9 Sep 2021 07:54:05 -0400 [thread overview]
Message-ID: <20210909115507.147917-48-sashal@kernel.org> (raw)
In-Reply-To: <20210909115507.147917-1-sashal@kernel.org>
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 323913ba13b3..dff08ff03278 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1488,7 +1488,7 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
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
next prev parent reply other threads:[~2021-09-09 12:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210909115507.147917-1-sashal@kernel.org>
2021-09-09 11:53 ` [PATCH AUTOSEL 5.4 012/109] netlink: Deal with ESRCH error in nlmsg_notify() Sasha Levin
2021-09-09 11:53 ` [PATCH AUTOSEL 5.4 026/109] bpf/tests: Fix copy-and-paste error in double word test Sasha Levin
2021-09-09 11:53 ` [PATCH AUTOSEL 5.4 027/109] bpf/tests: Do not PASS tests without actually testing the result Sasha Levin
2021-09-09 11:53 ` [PATCH AUTOSEL 5.4 040/109] samples: bpf: Fix tracex7 error raised on the missing argument Sasha Levin
2021-09-09 11:54 ` Sasha Levin [this message]
2021-09-09 11:54 ` [PATCH AUTOSEL 5.4 058/109] selftests/bpf: Fix xdp_tx.c prog section name Sasha Levin
2021-09-09 11:54 ` [PATCH AUTOSEL 5.4 090/109] selftests/bpf: Enlarge select() timeout for test_maps Sasha Levin
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