From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Helmut Grauer , Talat Batheesh , Saeed Mahameed , "David S. Miller" Subject: [PATCH 4.14 51/71] net/mlx5e: Fix fixpoint divide exception in mlx5e_am_stats_compare Date: Mon, 29 Jan 2018 13:57:19 +0100 Message-Id: <20180129123830.835568233@linuxfoundation.org> In-Reply-To: <20180129123827.271171825@linuxfoundation.org> References: <20180129123827.271171825@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Talat Batheesh [ Upstream commit e58edaa4863583b54409444f11b4f80dff0af1cd ] Helmut reported a bug about division by zero while running traffic and doing physical cable pull test. When the cable unplugged the ppms become zero, so when dividing the current ppms by the previous ppms in the next dim iteration there is division by zero. This patch prevent this division for both ppms and epms. Fixes: c3164d2fc48f ("net/mlx5e: Added BW check for DIM decision mechanism") Reported-by: Helmut Grauer Signed-off-by: Talat Batheesh Signed-off-by: Saeed Mahameed Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/mellanox/mlx5/core/en_rx_am.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx_am.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx_am.c @@ -197,9 +197,15 @@ static int mlx5e_am_stats_compare(struct return (curr->bpms > prev->bpms) ? MLX5E_AM_STATS_BETTER : MLX5E_AM_STATS_WORSE; + if (!prev->ppms) + return curr->ppms ? MLX5E_AM_STATS_BETTER : + MLX5E_AM_STATS_SAME; + if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms)) return (curr->ppms > prev->ppms) ? MLX5E_AM_STATS_BETTER : MLX5E_AM_STATS_WORSE; + if (!prev->epms) + return MLX5E_AM_STATS_SAME; if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms)) return (curr->epms < prev->epms) ? MLX5E_AM_STATS_BETTER :