From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=194.13.80.246 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793712102; b=ld/p99km7FyuEUa3mG6WLK+hr5iI/3+uj/sEvMzX58Q2Irp3L+oQmifuvhl7Z8X+QO69 nVbJsuSDioY4+rzhhFKTD7oBxFuIsA0dgpV7Mb79Coaq9q37fHTu62z9ggumlYoq3I/59 vCGOPxxVf9Ea5QJjuVvoUi8eJFD+NVsejabyMVH00HBC9pfcq9aX/9tvLdcxr1oXQdUIZ NroAoH5cEPOSbopXpHCW93zUd8zPdc//D1bXHsrryO8q3/OZke9C46Au1AnqBX3nnRDaM CT00r7mosi5topudgPcgYZ4SSaj9XgUvie7KqAqh7Il55Z/nDtmIdxzM2WqjudX52sA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793712102; h=DMARC-Filter:Received:DKIM-Signature:MIME-Version:Date:From:To:Cc: Subject:In-Reply-To:References:Message-ID:X-Sender:Content-Type: Content-Transfer-Encoding:X-Last-TLS-Session-Version; bh=4i7JeNgS3PqRN89dO+cpnOVMM3es4j1AZjQVBIQdGUs=; b=Ch7wppAAi3tPECy0zVGzjawA7z0tnN4bb9vPi29mp0CMFE+dBZi/1IQC2ZPYfkhQ0/kH OG5H2G8Cjxe1qrk5K0wPX9AFtiDy/j6S/PYHSxjB1tCenbDH7vGhu0iuQewDYuPx0CChp LeTqZOjZJBe4CNVzzeifIgVaGWgRIriBf93B/PZW5VhAL/G840bCAPtdg/wxp8dH0J7SV q+HzcR/xoli7nyiAfU3CKk81fF+V1RkNtNrhhRunT8ylSkZ6rIDLEiIASq6NoZh1R/bF1 BXISdUNVWOjX4Bf1Npu41lzRIZDVZMm3JgO5W+SSN18bGBBPK8DzY88f4C1y/3+GWlA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=tipi-net.de; spf=pass smtp.mailfrom=tipi-net.de; dkim=pass header.d=tipi-net.de header.i=@tipi-net.de header.a=rsa-sha256 header.s=dkim header.b="t+URNc/r"; arc=none smtp.remote-ip=194.13.80.246 Received: from mail.tipi-net.de (mail.tipi-net.de [194.13.80.246]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D630E606A32F; Tue, 3 Nov 2026 13:21:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org D630E606A32F Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=tipi-net.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=tipi-net.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=tipi-net.de header.i=@tipi-net.de header.a=rsa-sha256 header.s=dkim header.b=t+URNc/r Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 12ECFA1648; Tue, 03 Nov 2026 14:21:32 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tipi-net.de; s=dkim; t=1793712097; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=4i7JeNgS3PqRN89dO+cpnOVMM3es4j1AZjQVBIQdGUs=; b=t+URNc/r60MoZy96AxoqAKxv0aiqloRdmJ8e59KAjvzK44rrpCrCXMkv5SoSrCNrtzbeAa Vks8GVOW6j9f+vuuDEjqctWXcvSomv0vXToVIMFyptKvJQtvox49KLs9kRYFh42UsWAfSp Rj86BtBBuyrn1m8O29j/zUEqPgfCN/CS0yT1ia1e7HiiXMl0vlEcOs8Th2kR1Ok+sOwDnv BQrsLKs0luXhMQIqI3NqcpJjWvrR7fFScABtyplK2GhaWDrJ3LFYf9ikDPWcXjYQpQqKxN zxHfBgs9QdAF+cA+KtBYYIQtxg7o2WIATF4bMlBoejUxDN2a9ymII9qqmRRdtg== X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Date: Tue, 03 Nov 2026 14:21:32 +0100 From: Nicolai Buchwitz To: Maxime Chevallier Cc: Andrew Lunn , Jakub Kicinski , davem@davemloft.net, Eric Dumazet , Paolo Abeni , Simon Horman , Maxime Coquelin , Alexandre Torgue , Russell King , Lorenzo Bianconi , Magnus Leatti , thomas.petazzoni@bootlin.com, =?UTF-8?Q?Alexis_Lothor=C3=A9?= , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH net v2] net: stmmac: Clear DMA errors for multi-channel interrupts In-Reply-To: <20261103125430.962715-1-maxime.chevallier@bootlin.com> References: <20261103125430.962715-1-maxime.chevallier@bootlin.com> Message-ID: <4ae868bcfbdbc0f74ea5a9d57094e7fe@tipi-net.de> X-Sender: nb@tipi-net.de Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-Last-TLS-Session-Version: TLSv1.3 Hi Maxime On 3.11.2026 13:54, Maxime Chevallier wrote: > The Multi-MSI interrupt handler doesn't clear the DMA error interrupts, > and this leads to interrupt storms when one of these interrupts starts > firing : > > - The RBU (rx buff unav) which triggers under high traffic load > > This triggers easily with iperf3 and small udp packets, and shows > when running the netpoll kselftest > > - The RPS (rx process stop) which triggers when we stop the DMA RX. > > This one shows when restarting the RX logic without doing a down/up > cycle, like when attaching an XDP program. The XSK kselftests > triggers it. > > Let's make sure we clear these interrupts for multi-MSI cases, and call > stmmac_global_err() upon tx_hard_error to avoid possible races with > other interrupts/napi. > > For that introduce an "ERR" DMA dir, as we don't want to touch the > RI/TI bits when handling these interrupts. > > Both of the above storms have been found on dwmac-motorcomm (YT6801), > and are triggered by the xdp.py, xsk_reconfig.py, xdp_features.py, > ring_reconfig.py and netpoll_basic kernel selftests. > > This seems to only affect dwmac4, there's no multi-msi mode on > dwmac1000, and on dwxgmac these interrupts are masked as of today. > > Fixes: 6ccf12ae111e ("net: stmmac: use interrupt mode INTM=1 for > multi-MSI") > Signed-off-by: Maxime Chevallier > [...] Reviewed-by: Nicolai Buchwitz Thanks, Nicolai