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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Vasily Averin <vvs@virtuozzo.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 031/121] neigh_stat_seq_next() should increase position index
Date:   Tue, 29 Sep 2020 12:59:35 +0200
Message-Id: <20200929105931.722066488@linuxfoundation.org>
In-Reply-To: <20200929105930.172747117@linuxfoundation.org>
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From: Vasily Averin <vvs@virtuozzo.com>

[ Upstream commit 1e3f9f073c47bee7c23e77316b07bc12338c5bba ]

if seq_file .next fuction does not change position index,
read after some lseek can generate unexpected output.

https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/core/neighbour.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 6578d1f8e6c4a..d267dc04d9f74 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2797,6 +2797,7 @@ static void *neigh_stat_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 		*pos = cpu+1;
 		return per_cpu_ptr(tbl->stats, cpu);
 	}
+	(*pos)++;
 	return NULL;
 }
 
-- 
2.25.1