From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Roman Gushchin <guro@fb.com>, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Sasha Levin <sashal@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH AUTOSEL 5.0 23/34] bpf: Fix preempt_enable_no_resched() abuse
Date: Thu, 16 May 2019 07:39:20 -0400 [thread overview]
Message-ID: <20190516113932.8348-23-sashal@kernel.org> (raw)
In-Reply-To: <20190516113932.8348-1-sashal@kernel.org>
From: Peter Zijlstra <peterz@infradead.org>
[ Upstream commit 0edd6b64d1939e9e9168ff27947995bb7751db5d ]
Unless the very next line is schedule(), or implies it, one must not use
preempt_enable_no_resched(). It can cause a preemption to go missing and
thereby cause arbitrary delays, breaking the PREEMPT=y invariant.
Cc: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/bpf.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e734f163bd0b9..1fbd7672e4b37 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -455,7 +455,7 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
} \
_out: \
rcu_read_unlock(); \
- preempt_enable_no_resched(); \
+ preempt_enable(); \
_ret; \
})
--
2.20.1
prev parent reply other threads:[~2019-05-16 11:47 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190516113932.8348-1-sashal@kernel.org>
2019-05-16 11:39 ` [PATCH AUTOSEL 5.0 22/34] tools: bpftool: fix infinite loop in map create Sasha Levin
2019-05-16 11:39 ` Sasha Levin [this message]
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