From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout1.w1.samsung.com (mailout1.w1.samsung.com [210.118.77.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7F3793101BC for ; Fri, 19 Sep 2025 12:25:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.118.77.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758284752; cv=none; b=kYc6lOTCzzb3X5x2tUIXsRmOtxl+7WESfocqVJuy5Is3Ko+atoa0+iDHTVwSXY+VU2ZZ7nQKJW7S+RUMmhDETF8MA9J3efJqPLfoCCOSk5J7eULBHOtwFIg2FdWzpUhMqvy+nsGt7yRXVY+dJpi+d+JWRud71R1DrzoLR0656Mk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758284752; c=relaxed/simple; bh=vYAp2B9j9qt6EzipuEAQ4I8GMhjImCOP7cCNEmb6aqM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:From:In-Reply-To: Content-Type:References; b=soGiiwwY1y/zNgEDZ0mONpie7Zgu+YKOg5P1uJExkZWNhQfxjuJKKZkPC2nKuG+FZOg6q/m9mBfza5XiWk/cficU0JqXHaF4HwEuLDZ0zIqhn/9iTpVLnYhNM5SQYUdrr7hpX7BgrSAswLo4y1H5/f9Nu/y4WSozob0gf9js1z4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=F+Xk3glO; arc=none smtp.client-ip=210.118.77.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="F+Xk3glO" Received: from eucas1p2.samsung.com (unknown [182.198.249.207]) by mailout1.w1.samsung.com (KnoxPortal) with ESMTP id 20250919122548euoutp01206cd0bf6c561ed961a0fda06dc2719a~mrqm-kthf0436304363euoutp01S for ; Fri, 19 Sep 2025 12:25:48 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20250919122548euoutp01206cd0bf6c561ed961a0fda06dc2719a~mrqm-kthf0436304363euoutp01S DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1758284748; bh=xSKIjPyrA9OEriZopMFlNAyxpcs3It57Viautl04tXI=; h=Date:Subject:To:Cc:From:In-Reply-To:References:From; b=F+Xk3glO2cgewx7e1iKp9JX1qLwGgul+qkbyUSnqJFUujLqQCD+JHqtjvA6C3plYu tb6XPaK8AiHnvh314NhvSLRtAY4447tqqdUgXWoNLeXPOAmqkxv+8RUKDUaNPnreiy X7XwGpQUJq2P149JjEd996iP8UKxN6e0DQeU8y+U= Received: from eusmtip2.samsung.com (unknown [203.254.199.222]) by eucas1p1.samsung.com (KnoxPortal) with ESMTPA id 20250919122548eucas1p1ef58c5c747bee71acd5f9d6476e7c29c~mrqmcuafh2548325483eucas1p1m; Fri, 19 Sep 2025 12:25:48 +0000 (GMT) Received: from [106.210.134.192] (unknown [106.210.134.192]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20250919122546eusmtip2896ff33c135295219ae1f797110c7a94~mrqk2ipmP1691216912eusmtip2-; Fri, 19 Sep 2025 12:25:46 +0000 (GMT) Message-ID: <7605453a-ac62-497b-b77a-76d73e9a6741@samsung.com> Date: Fri, 19 Sep 2025 14:25:45 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Betterbird (Windows) Subject: Re: [PATCH net-next] net: spacemit: Make stats_lock softirq-safe To: Vivian Wang , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Yixun Lan , Maxime Chevallier , Troy Mitchell , Vadim Fedorenko Cc: netdev@vger.kernel.org, linux-riscv@lists.infradead.org, spacemit@lists.linux.dev, linux-kernel@vger.kernel.org, Vivian Wang Content-Language: en-US From: Marek Szyprowski In-Reply-To: <20250919-k1-ethernet-fix-lock-v1-1-c8b700aa4954@iscas.ac.cn> Content-Transfer-Encoding: 7bit X-CMS-MailID: 20250919122548eucas1p1ef58c5c747bee71acd5f9d6476e7c29c X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20250919120522eucas1p224c42d0cc2a59903d85e6c80dfdfa727 X-EPHeader: CA X-CMS-RootMailID: 20250919120522eucas1p224c42d0cc2a59903d85e6c80dfdfa727 References: <20250919-k1-ethernet-fix-lock-v1-1-c8b700aa4954@iscas.ac.cn> On 19.09.2025 14:04, Vivian Wang wrote: > While most of the statistics functions (emac_get_stats64() and such) are > called with softirqs enabled, emac_stats_timer() is, as its name > suggests, also called from a timer, i.e. called in softirq context. > > All of these take stats_lock. Therefore, make stats_lock softirq-safe by > changing spin_lock() into spin_lock_bh() for the functions that get > statistics. > > Also, instead of directly calling emac_stats_timer() in emac_up() and > emac_resume(), set the timer to trigger instead, so that > emac_stats_timer() is only called from the timer. It will keep using > spin_lock(). > > This fixes a lockdep warning, and potential deadlock when stats_timer is > triggered in the middle of getting statistics. > > Fixes: bfec6d7f2001 ("net: spacemit: Add K1 Ethernet MAC") > Reported-by: Marek Szyprowski > Closes: https://lore.kernel.org/all/a52c0cf5-0444-41aa-b061-a0a1d72b02fe@samsung.com/ > Signed-off-by: Vivian Wang Tested-by: Marek Szyprowski > --- > Thanks a lot for catching this, Marek! > --- > drivers/net/ethernet/spacemit/k1_emac.c | 30 +++++++++++++++--------------- > 1 file changed, 15 insertions(+), 15 deletions(-) > > diff --git a/drivers/net/ethernet/spacemit/k1_emac.c b/drivers/net/ethernet/spacemit/k1_emac.c > index 928fea02198c3754f63a7b33fc25c5dd8c2b59f9..e1c5faff3b71c7d4ceba2ea194d9c888f0e71b70 100644 > --- a/drivers/net/ethernet/spacemit/k1_emac.c > +++ b/drivers/net/ethernet/spacemit/k1_emac.c > @@ -135,7 +135,7 @@ struct emac_priv { > bool flow_control_autoneg; > u8 flow_control; > > - /* Hold while touching hardware statistics */ > + /* Softirq-safe, hold while touching hardware statistics */ > spinlock_t stats_lock; > }; > > @@ -1239,7 +1239,7 @@ static void emac_get_stats64(struct net_device *dev, > /* This is the only software counter */ > storage->tx_dropped = emac_get_stat_tx_drops(priv); > > - spin_lock(&priv->stats_lock); > + spin_lock_bh(&priv->stats_lock); > > emac_stats_update(priv); > > @@ -1261,7 +1261,7 @@ static void emac_get_stats64(struct net_device *dev, > storage->rx_missed_errors = rx_stats->stats.rx_drp_fifo_full_pkts; > storage->rx_missed_errors += rx_stats->stats.rx_truncate_fifo_full_pkts; > > - spin_unlock(&priv->stats_lock); > + spin_unlock_bh(&priv->stats_lock); > } > > static void emac_get_rmon_stats(struct net_device *dev, > @@ -1275,7 +1275,7 @@ static void emac_get_rmon_stats(struct net_device *dev, > > *ranges = emac_rmon_hist_ranges; > > - spin_lock(&priv->stats_lock); > + spin_lock_bh(&priv->stats_lock); > > emac_stats_update(priv); > > @@ -1294,7 +1294,7 @@ static void emac_get_rmon_stats(struct net_device *dev, > rmon_stats->hist[5] = rx_stats->stats.rx_1024_1518_pkts; > rmon_stats->hist[6] = rx_stats->stats.rx_1519_plus_pkts; > > - spin_unlock(&priv->stats_lock); > + spin_unlock_bh(&priv->stats_lock); > } > > static void emac_get_eth_mac_stats(struct net_device *dev, > @@ -1307,7 +1307,7 @@ static void emac_get_eth_mac_stats(struct net_device *dev, > tx_stats = &priv->tx_stats; > rx_stats = &priv->rx_stats; > > - spin_lock(&priv->stats_lock); > + spin_lock_bh(&priv->stats_lock); > > emac_stats_update(priv); > > @@ -1325,7 +1325,7 @@ static void emac_get_eth_mac_stats(struct net_device *dev, > mac_stats->FramesAbortedDueToXSColls = > tx_stats->stats.tx_excessclsn_pkts; > > - spin_unlock(&priv->stats_lock); > + spin_unlock_bh(&priv->stats_lock); > } > > static void emac_get_pause_stats(struct net_device *dev, > @@ -1338,14 +1338,14 @@ static void emac_get_pause_stats(struct net_device *dev, > tx_stats = &priv->tx_stats; > rx_stats = &priv->rx_stats; > > - spin_lock(&priv->stats_lock); > + spin_lock_bh(&priv->stats_lock); > > emac_stats_update(priv); > > pause_stats->tx_pause_frames = tx_stats->stats.tx_pause_pkts; > pause_stats->rx_pause_frames = rx_stats->stats.rx_pause_pkts; > > - spin_unlock(&priv->stats_lock); > + spin_unlock_bh(&priv->stats_lock); > } > > /* Other statistics that are not derivable from standard statistics */ > @@ -1393,14 +1393,14 @@ static void emac_get_ethtool_stats(struct net_device *dev, > u64 *rx_stats = (u64 *)&priv->rx_stats; > int i; > > - spin_lock(&priv->stats_lock); > + spin_lock_bh(&priv->stats_lock); > > emac_stats_update(priv); > > for (i = 0; i < ARRAY_SIZE(emac_ethtool_rx_stats); i++) > data[i] = rx_stats[emac_ethtool_rx_stats[i].offset]; > > - spin_unlock(&priv->stats_lock); > + spin_unlock_bh(&priv->stats_lock); > } > > static int emac_ethtool_get_regs_len(struct net_device *dev) > @@ -1769,7 +1769,7 @@ static int emac_up(struct emac_priv *priv) > > netif_start_queue(ndev); > > - emac_stats_timer(&priv->stats_timer); > + mod_timer(&priv->stats_timer, jiffies); > > return 0; > > @@ -1807,14 +1807,14 @@ static int emac_down(struct emac_priv *priv) > > /* Update and save current stats, see emac_stats_update() for usage */ > > - spin_lock(&priv->stats_lock); > + spin_lock_bh(&priv->stats_lock); > > emac_stats_update(priv); > > priv->tx_stats_off = priv->tx_stats; > priv->rx_stats_off = priv->rx_stats; > > - spin_unlock(&priv->stats_lock); > + spin_unlock_bh(&priv->stats_lock); > > pm_runtime_put_sync(&pdev->dev); > return 0; > @@ -2111,7 +2111,7 @@ static int emac_resume(struct device *dev) > > netif_device_attach(ndev); > > - emac_stats_timer(&priv->stats_timer); > + mod_timer(&priv->stats_timer, jiffies); > > return 0; > } > > --- > base-commit: 315f423be0d1ebe720d8fd4fa6bed68586b13d34 > change-id: 20250919-k1-ethernet-fix-lock-c99681a9aa5d > > Best regards, Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland