From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 2697E606A330 for ; Tue, 3 Nov 2026 13:21:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=XlqQRKdp; 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 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:Message-ID:References:In-Reply-To:Subject:Cc:To:From:Date: MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=4i7JeNgS3PqRN89dO+cpnOVMM3es4j1AZjQVBIQdGUs=; b=XlqQRKdpqUoufR P4cqxWfMPFR17ls6hmh643dfPdP++G8FtcKYkESIC7LMrK0olexJV66NtepPTIBRjizwGwsJ01mvi yEwznQ8vzNnwdsMdmmpYfy69rkwic+2EXH+R7Pj/R7hYv3rUgN8IQVv4TsTML39QjRPs0iscxKcUp VXBpn0Q7l54funP85Ty/UTPmJgi7IQQBNpdSyVXPJzgztWj5jaPedAKRY4+nY7LiuEOpE+9Zc4AQt E0u49B2AkxdzpgpwPjN6L7jzKK95laMrGHyv3sluluNW1GRUXoY1LIBhsl+BJ7Z+IkWmqMdQXEGNe lGt5XacxhXq9zsfy1oig==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOESO-00000002Wwn-10JA; Tue, 03 Nov 2026 13:21:44 +0000 Received: from mail.tipi-net.de ([2a03:4000:43:185::1]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOESL-00000002Wvp-37ho for linux-arm-kernel@lists.infradead.org; Tue, 03 Nov 2026 13:21:43 +0000 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-Archived-By: 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261103_052141_944139_0725BE23 X-CRM114-Status: GOOD ( 15.93 ) X-Spam-Score: -2.1 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-10.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 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