From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 161C5380FEB; Mon, 6 Jul 2026 15:05:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783350356; cv=none; b=NNFcA2QgHQwEAV5PqbSlgoIlbbi/FNdPlg1QPpt0j7IDZZ65C2feFM6UaRnV5qi7MJXGUKVfPCA9jN1spofaN6ozFj1sRdRkmthR5UKo4atdWMeZgyzg5uuJ3ylZDO6Mym6x0H9ppQFsF+2PB9kPC1lLhFlAnZl31iAkadmSitI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783350356; c=relaxed/simple; bh=3yi8neAEE9rEq0mxmjpaiKYd96ZV5xiHUgR7phnh+HY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hYM/DW9RSycYeJlFYD8ppb84oLsdsuhw8D9niByrc7Owp90mLOfJM64am8Si85j2ICrdAlwgz0Dh+ggiNnE5c3EpGFnaqB9xx9TRMRQN7b0ZOyPMBZfatdGWzbyUv6QVTR1L/Ke6vcWsxR6AO4PK4zFTApUbW/a2Tp9m1xJSnYc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=VTBiBrwE; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=P9d7GLAb; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="VTBiBrwE"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="P9d7GLAb" Date: Mon, 6 Jul 2026 17:05:52 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1783350353; 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: in-reply-to:in-reply-to:references:references; bh=NB9C1tjmGRHLySf+l2Zt8ileBtf+TYUJy39INOr86Rg=; b=VTBiBrwEo17Mp0HQTuYwb3bfzd/zrFr8t8ZTDKDypENitm0+Tnkk2+H68X4nS0AayUt6HM zxCU0OHI8K1adKE2YYCFU5nJdq3/Sl1nH1nw9pd5xwiFndFn3hhg/AGZu/1ftTLRmTVfMK bd46WKl2tO4PyLyDznw4dUxapNUGv9Y/1NHNDGcEgOSp8DcAvTHmXD3Qw0v+iD+Lfv5CuK SE3yVClhbRdjccY12f5szI5t+OE8fEc/4fk7povRHWvuphZ7x35kgVb/R59ZmswD2eJgWP yqJD4h9T1WdoNY26uR0LRwgmlzamqE5Gb3U7jPzq1hFTxVqX+gRDN+Nbk9QKfA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1783350353; 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: in-reply-to:in-reply-to:references:references; bh=NB9C1tjmGRHLySf+l2Zt8ileBtf+TYUJy39INOr86Rg=; b=P9d7GLAbFTnLUHFuMicc7kn2osB9FQ+NuT3a7SjkC6F/47wbb8306piJiBgy8MPLHY9rIJ kk/YwkP3tYClXWDw== From: Sebastian Andrzej Siewior To: christian.taedcke@weidmueller.com Cc: christian.taedcke-oss@weidmueller.com, =?utf-8?B?VGjDqW8=?= Lebrun , Conor Dooley , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Kevin Hao , Simon Horman , Clark Williams , Steven Rostedt , Robert Hancock , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, stable@vger.kernel.org Subject: Re: [PATCH net 2/2] net: macb: mask TXUBR during TX NAPI poll to prevent IRQ storms Message-ID: <20260706150552.EomovsBn@linutronix.de> References: <20260706-upstreaming-macb-irq-storm-v1-0-ab3115b5a13a@weidmueller.com> <20260706-upstreaming-macb-irq-storm-v1-2-ab3115b5a13a@weidmueller.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260706-upstreaming-macb-irq-storm-v1-2-ab3115b5a13a@weidmueller.com> On 2026-07-06 16:02:15 [+0200], Christian Taedcke via B4 Relay wrote: > From: Christian Taedcke > > macb_interrupt() defers TX completion handling to NAPI, but when it > schedules the poll it only masks TCOMP, even though TXUBR is enabled > alongside it (both are part of MACB_TX_INT_FLAGS). macb_tx_poll() is > asymmetric in the same way and only re-enables TCOMP. TXUBR is thus > left unmasked while responsibility for handling it has been deferred > to NAPI. So this is not a race condition, this is always a failure? Sebastian