From: Jijie Shao Date: Wed, 6 Aug 2025 10:27:57 +0000 (+0800) Subject: net: hibmcge: fix the division by zero issue X-Git-Tag: v6.17-rc2~17^2~33^2~1 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7004b26f0b64331143eb0b312e77a357a11427ce;p=users%2Fgriffoul%2Flinux.git net: hibmcge: fix the division by zero issue When the network port is down, the queue is released, and ring->len is 0. In debugfs, hbg_get_queue_used_num() will be called, which may lead to a division by zero issue. This patch adds a check, if ring->len is 0, hbg_get_queue_used_num() directly returns 0. Fixes: 40735e7543f9 ("net: hibmcge: Implement .ndo_start_xmit function") Signed-off-by: Jijie Shao Reviewed-by: Simon Horman Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/ethernet/hisilicon/hibmcge/hbg_txrx.h b/drivers/net/ethernet/hisilicon/hibmcge/hbg_txrx.h index 2883a5899ae29..8b6110599e10d 100644 --- a/drivers/net/ethernet/hisilicon/hibmcge/hbg_txrx.h +++ b/drivers/net/ethernet/hisilicon/hibmcge/hbg_txrx.h @@ -29,7 +29,12 @@ static inline bool hbg_fifo_is_full(struct hbg_priv *priv, enum hbg_dir dir) static inline u32 hbg_get_queue_used_num(struct hbg_ring *ring) { - return (ring->ntu + ring->len - ring->ntc) % ring->len; + u32 len = READ_ONCE(ring->len); + + if (!len) + return 0; + + return (READ_ONCE(ring->ntu) + len - READ_ONCE(ring->ntc)) % len; } netdev_tx_t hbg_net_start_xmit(struct sk_buff *skb, struct net_device *netdev);