From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [217.70.183.195]) (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 A691B201271; Tue, 22 Apr 2025 14:00:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.195 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745330453; cv=none; b=CmEPjkSHw60XVkN3i4nGy08l2Lc2RZ1EXsNoasDta1Hhic4HMmMYLuOB/4yMk7vkEn4lkcRCWFgXISxoTTVgE0eodgmvX6mA2Ci4b684Y/TxPYflMHEQV+4rc3Na8uWtEuozZQLwhIPZJyZaJKjYg2bOdDTYMxhafkjRmo+AuKU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745330453; c=relaxed/simple; bh=y9K5KER5IuQLzh5nwL4+Rt33mfTaJJi1XfUMw3a1O9c=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=fZCbgSwAOT98DT1Yz4rIXCpGd153AlqrJ+F/Eey1YiPxcbB21OUC8dhSNe5spXZM3dMLzakxNMjqJDOuNbF2QFBmDzaaR+IwVmppfhhRbhUy/5H7k1HvXgiH5d5KljHE7uBeDqnGTSghQrEMbukXKZg6wsgs6gEdGQwPoRRii+k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=D/iYA3tl; arc=none smtp.client-ip=217.70.183.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="D/iYA3tl" Received: by mail.gandi.net (Postfix) with ESMTPSA id 703CE1FD49; Tue, 22 Apr 2025 14:00:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1745330449; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=weXN4IQwhPqB9cEpvD0ds3Xd1d/HGeU1/wCq5TjQLSw=; b=D/iYA3tlYeAcV2qo72QQQOulGZa0PhsLCGGvS2XtBrOpw9eF8L2L4D9/s5tHpodwvgqhjl kmBrBYJIQ9O+w0G7V/e/s4rTEx8ePugOcsOi/axI+3tvbIrj8BoJ2EHiUuVUAfyCCTQ1Z7 rHAPcZtVSBvSeXGSXhzHxxW8GBHGBR7+3gXQTL9TnRkvDXOWr2Siu5T35DUTEHp+LW3JXS hmoxGmVBlDWPqoTeH8thQsfugxGpqtB24ZOdsuZS9I+BxpLnADoo13MVbLXOi795wH2MfT QbOwyI/TRn12q6AFSlFhYeLjVZ99b5PZtg/S9/lbG60a2hZrhVf9WlN3G6wNNQ== Date: Tue, 22 Apr 2025 16:00:46 +0200 From: Maxime Chevallier To: Louis-Alexis Eyraud Cc: Felix Fietkau , Sean Wang , Lorenzo Bianconi , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Matthias Brugger , AngeloGioacchino Del Regno , Biao Huang , Yinghua Pan , kernel@collabora.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Subject: Re: [PATCH 1/2] net: ethernet: mtk-star-emac: fix spinlock recursion issues on rx/tx poll Message-ID: <20250422160046.73aa854a@fedora.home> In-Reply-To: <20250422-mtk_star_emac-fix-spinlock-recursion-issue-v1-1-1e94ea430360@collabora.com> References: <20250422-mtk_star_emac-fix-spinlock-recursion-issue-v1-0-1e94ea430360@collabora.com> <20250422-mtk_star_emac-fix-spinlock-recursion-issue-v1-1-1e94ea430360@collabora.com> Organization: Bootlin X-Mailer: Claws Mail 4.3.1 (GTK 3.24.43; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddvgeefleduucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpeffhffvvefukfgjfhhoofggtgfgsehtjeertdertddvnecuhfhrohhmpeforgigihhmvgcuvehhvghvrghllhhivghruceomhgrgihimhgvrdgthhgvvhgrlhhlihgvrhessghoohhtlhhinhdrtghomheqnecuggftrfgrthhtvghrnhepgeevledtvdevueehhfevhfelhfekveeftdfgiedufeffieeltddtgfefuefhueeknecukfhppedvrgdtudemtggsudelmeekugegheemgeeltddtmeeiheeikeemvdelsgdumeelvghfheemvgektgejnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepvdgrtddumegtsgduleemkegugeehmeegledttdemieehieekmedvlegsudemlegvfhehmegvkegtjedphhgvlhhopehfvgguohhrrgdrhhhomhgvpdhmrghilhhfrhhomhepmhgrgihimhgvrdgthhgvvhgrlhhlihgvrhessghoohhtlhhinhdrtghomhdpnhgspghrtghpthhtohepudekpdhrtghpthhtoheplhhouhhishgrlhgvgihishdrvgihrhgruhgusegtohhllhgrsghorhgrrdgtohhmpdhrtghpthhtohepnhgsugesnhgsugdrnhgrmhgvpdhrtghpthhtohepshgvrghnrdifrghnghesmhgvughir ghtvghkrdgtohhmpdhrtghpthhtoheplhhorhgvnhiioheskhgvrhhnvghlrdhorhhgpdhrtghpthhtoheprghnughrvgifodhnvghtuggvvheslhhunhhnrdgthhdprhgtphhtthhopegurghvvghmsegurghvvghmlhhofhhtrdhnvghtpdhrtghpthhtohepvgguuhhmrgiivghtsehgohhoghhlvgdrtghomhdprhgtphhtthhopehkuhgsrgeskhgvrhhnvghlrdhorhhg X-GND-Sasl: maxime.chevallier@bootlin.com Hi Louis-Alexis :) On Tue, 22 Apr 2025 15:03:38 +0200 Louis-Alexis Eyraud wrote: > Use spin_lock_irqsave and spin_unlock_irqrestore instead of spin_lock > and spin_unlock in mtk_star_emac driver to avoid spinlock recursion > occurrence that can happen when enabling the DMA interrupts again in > rx/tx poll. > > ``` > BUG: spinlock recursion on CPU#0, swapper/0/0 > lock: 0xffff00000db9cf20, .magic: dead4ead, .owner: swapper/0/0, > .owner_cpu: 0 > CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted > 6.15.0-rc2-next-20250417-00001-gf6a27738686c-dirty #28 PREEMPT > Hardware name: MediaTek MT8365 Open Platform EVK (DT) > Call trace: > show_stack+0x18/0x24 (C) > dump_stack_lvl+0x60/0x80 > dump_stack+0x18/0x24 > spin_dump+0x78/0x88 > do_raw_spin_lock+0x11c/0x120 > _raw_spin_lock+0x20/0x2c > mtk_star_handle_irq+0xc0/0x22c [mtk_star_emac] > __handle_irq_event_percpu+0x48/0x140 > handle_irq_event+0x4c/0xb0 > handle_fasteoi_irq+0xa0/0x1bc > handle_irq_desc+0x34/0x58 > generic_handle_domain_irq+0x1c/0x28 > gic_handle_irq+0x4c/0x120 > do_interrupt_handler+0x50/0x84 > el1_interrupt+0x34/0x68 > el1h_64_irq_handler+0x18/0x24 > el1h_64_irq+0x6c/0x70 > regmap_mmio_read32le+0xc/0x20 (P) > _regmap_bus_reg_read+0x6c/0xac > _regmap_read+0x60/0xdc > regmap_read+0x4c/0x80 > mtk_star_rx_poll+0x2f4/0x39c [mtk_star_emac] > __napi_poll+0x38/0x188 > net_rx_action+0x164/0x2c0 > handle_softirqs+0x100/0x244 > __do_softirq+0x14/0x20 > ____do_softirq+0x10/0x20 > call_on_irq_stack+0x24/0x64 > do_softirq_own_stack+0x1c/0x40 > __irq_exit_rcu+0xd4/0x10c > irq_exit_rcu+0x10/0x1c > el1_interrupt+0x38/0x68 > el1h_64_irq_handler+0x18/0x24 > el1h_64_irq+0x6c/0x70 > cpuidle_enter_state+0xac/0x320 (P) > cpuidle_enter+0x38/0x50 > do_idle+0x1e4/0x260 > cpu_startup_entry+0x34/0x3c > rest_init+0xdc/0xe0 > console_on_rootfs+0x0/0x6c > __primary_switched+0x88/0x90 > ``` > > Fixes: 0a8bd81fd6aa ("net: ethernet: mtk-star-emac: separate tx/rx handling with two NAPIs") > Signed-off-by: Louis-Alexis Eyraud As this is a fix, you need to indicate in your subject that you're targetting the "net" tree, something like : [PATCH net 1/2] net: ethernet: mtk-star-emac: fix spinlock recursion issues on rx/tx poll > --- > drivers/net/ethernet/mediatek/mtk_star_emac.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/ethernet/mediatek/mtk_star_emac.c b/drivers/net/ethernet/mediatek/mtk_star_emac.c > index 76f202d7f05537642ec294811ace2ad4a7eae383..41d6af31027f4d827dbfdfecdb7de44326bb3de1 100644 > --- a/drivers/net/ethernet/mediatek/mtk_star_emac.c > +++ b/drivers/net/ethernet/mediatek/mtk_star_emac.c > @@ -1163,6 +1163,7 @@ static int mtk_star_tx_poll(struct napi_struct *napi, int budget) > struct net_device *ndev = priv->ndev; > unsigned int head = ring->head; > unsigned int entry = ring->tail; > + unsigned long flags = 0; You don't need to init flags to 0 > > while (entry != head && count < (MTK_STAR_RING_NUM_DESCS - 1)) { > ret = mtk_star_tx_complete_one(priv); > @@ -1182,9 +1183,9 @@ static int mtk_star_tx_poll(struct napi_struct *napi, int budget) > netif_wake_queue(ndev); > > if (napi_complete(napi)) { > - spin_lock(&priv->lock); > + spin_lock_irqsave(&priv->lock, flags); > mtk_star_enable_dma_irq(priv, false, true); > - spin_unlock(&priv->lock); > + spin_unlock_irqrestore(&priv->lock, flags); > } > > return 0; > @@ -1342,15 +1343,16 @@ static int mtk_star_rx_poll(struct napi_struct *napi, int budget) > { > struct mtk_star_priv *priv; > int work_done = 0; > + unsigned long flags = 0; There's a rule in netdev that definitions must be ordered from longest to shortest lines (reverse xmas tree, or RCT), so you should have in the end : struct mtk_star_priv *priv; unsigned long flags; int work_done = 0; > > priv = container_of(napi, struct mtk_star_priv, rx_napi); > > work_done = mtk_star_rx(priv, budget); > if (work_done < budget) { > napi_complete_done(napi, work_done); > - spin_lock(&priv->lock); > + spin_lock_irqsave(&priv->lock, flags); > mtk_star_enable_dma_irq(priv, true, false); > - spin_unlock(&priv->lock); > + spin_unlock_irqrestore(&priv->lock, flags); > } > > return work_done; > Besides these small comments, the patch looks correct to me :) Regards, Maxime