From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f52.google.com (mail-qv1-f52.google.com [209.85.219.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1597224FC03 for ; Mon, 3 Mar 2025 16:46:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741020375; cv=none; b=QxORuWFg7NmPwHG2ARgVo2meMtTnu/oEKXjm4uqdCLUAyZ2YPzBw+VLAbNn03hwbDA0dIOd7M7EaqfJ5rf5VGVcluU314p+oqhLZwb26uIvfhKOYZLnbcwVxMOfbqvjY5oIrX9gpnA3lDxs1qpeA6AZuqFSsLjJYFtuYY75dF7o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741020375; c=relaxed/simple; bh=4a3Js/QSUPm1CO0AmuaBEQTQLE/ky9K8nLFdDZq450M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QHHflSydyn/qcgVEZMRE9f9XqWyHpuyt95s9xK8OqEe/qZnnWMdRTuwGC65KF7acazZjnvblDZ6QklTIboeukT8rCRYTguv07RpVQVwuRTRLgS6VNoKg6yu5PuW7wANU2YxJuzD8PYaBLaQe6J5+hu3IXXpDS7hk14DUl9vp77A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fastly.com; spf=pass smtp.mailfrom=fastly.com; dkim=pass (1024-bit key) header.d=fastly.com header.i=@fastly.com header.b=xd/JcQ6h; arc=none smtp.client-ip=209.85.219.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fastly.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fastly.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=fastly.com header.i=@fastly.com header.b="xd/JcQ6h" Received: by mail-qv1-f52.google.com with SMTP id 6a1803df08f44-6dd049b5428so42868216d6.2 for ; Mon, 03 Mar 2025 08:46:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastly.com; s=google; t=1741020373; x=1741625173; darn=lists.linux.dev; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date:from:to:cc :subject:date:message-id:reply-to; bh=8X1eRghCbAiXOwCl3h9CNpVTl3lfWmjRfbNCLQzdf/o=; b=xd/JcQ6hpk0y+8Y9sgUCageeVcwIXWDsFg/Yb3xISwbod3KJKEMUm4xrDoz2ja2kly 3CI3YSJdxgXlJTSsFuTlc5Cp2/Tf6DpQrfQgrYkvFJspj8JH7t2zOL+H0gpWH3mkLEfj TpM06KF1bo4VEqyISElNd26Ays/FD1xzYXndI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741020373; x=1741625173; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=8X1eRghCbAiXOwCl3h9CNpVTl3lfWmjRfbNCLQzdf/o=; b=h/wogyYq8eqKmGmSRL1tfqLVthMOtbCiXO+RuQIL/ORpP5INBbHpdpmor7Nw2QNYjq gl4zmqFXdy/YHxJbELzk59Z2JzRx58ILergodi/btPN1Ow1yiSxTm2Xl3XcklpnRRdEJ kySFpv8az/afhGpwO6Hf5vfWqarhFJQcnHpCC0sny9YScykvTC2YCovvcjBWoLhhQNGz L8k1UzyX3X/Q0jPO4Ma1iOihg+4FabXaADhsqDK5nyGEp81a4jleyMftFLs2NZDavEte q8HU1ZnaKfs21NHkkh1ASwEfFQymIW1oK7KA7nrkgL45/TcvodEm1I0vs817qncDvPP/ Vz2A== X-Forwarded-Encrypted: i=1; AJvYcCXfGpDoKEZ/e0jPBRUVgTyYh2WP4pz+Ywj9qPegsdMn1Sylu4/mdTOBuI1/VKdYLwLOQ3cwZa301Y3j8gvJlg==@lists.linux.dev X-Gm-Message-State: AOJu0Yy5+J8pqbVocOptMnZ/o4Lx/U7yPqr1Sln0WePy6/xxdLpaYTss pNF0K70UHQ7e+bq9PSUC6k7lQmZCXZBkaI95Tb0Zvau8t47YwhuaEiuCz03RC+Q= X-Gm-Gg: ASbGncsCDmlhtfi1cYIBNbxhkP6PaqEa0XyMcQMtwC5a6znEG8KOUpyVmmBrGPh1hmH n7TtCmK9CkT67UDIdmVma9ptkanUd9PNoNJ+t/QwCOnz/m90nw+/aN64nz57bhJuA4zrsQA1cyj H3VYuqnzlF4Y40r1gP2ni4+RTLjWvJdey/Tm6qT5+qlGMZkV5aNaXm4cOOSbdxqz2HO4BOsDJGv yZ/AlG6KBLqkDtfNHd6K01YspzPvMouTaFKnt9DZvT0KPIpKPRodaP6pNrELDwkfdbOcpLgXGoe /3UyDpAb0TAMT9qPCRlUdfOcV6BASFt8sPx3hQkqcyjuma7gmajCWIuVxv3zeenmHsMuXmxzmTj K2VHHi6I= X-Google-Smtp-Source: AGHT+IHkzyITDdW3vLOmKpMop+SV7m+wXZtHTB86svSFry2DpAQLcSAU+s3Ys44u2tdDtQuD6QzsPg== X-Received: by 2002:ad4:5de6:0:b0:6cb:c54c:b782 with SMTP id 6a1803df08f44-6e8a0d84e3dmr230430596d6.32.1741020372960; Mon, 03 Mar 2025 08:46:12 -0800 (PST) Received: from LQ3V64L9R2 (ool-44c5a22e.dyn.optonline.net. [68.197.162.46]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6e897653667sm54834896d6.32.2025.03.03.08.46.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Mar 2025 08:46:12 -0800 (PST) Date: Mon, 3 Mar 2025 11:46:10 -0500 From: Joe Damato To: Jakub Kicinski Cc: netdev@vger.kernel.org, mkarsten@uwaterloo.ca, gerhard@engleder-embedded.com, jasowang@redhat.com, xuanzhuo@linux.alibaba.com, mst@redhat.com, leiyang@redhat.com, Eugenio =?iso-8859-1?Q?P=E9rez?= , Andrew Lunn , "David S. Miller" , Eric Dumazet , Paolo Abeni , "open list:VIRTIO CORE AND NET DRIVERS" , open list Subject: Re: [PATCH net-next v5 3/4] virtio-net: Map NAPIs to queues Message-ID: Mail-Followup-To: Joe Damato , Jakub Kicinski , netdev@vger.kernel.org, mkarsten@uwaterloo.ca, gerhard@engleder-embedded.com, jasowang@redhat.com, xuanzhuo@linux.alibaba.com, mst@redhat.com, leiyang@redhat.com, Eugenio =?iso-8859-1?Q?P=E9rez?= , Andrew Lunn , "David S. Miller" , Eric Dumazet , Paolo Abeni , "open list:VIRTIO CORE AND NET DRIVERS" , open list References: <20250227185017.206785-1-jdamato@fastly.com> <20250227185017.206785-4-jdamato@fastly.com> <20250228182759.74de5bec@kernel.org> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250228182759.74de5bec@kernel.org> On Fri, Feb 28, 2025 at 06:27:59PM -0800, Jakub Kicinski wrote: > On Thu, 27 Feb 2025 18:50:13 +0000 Joe Damato wrote: > > @@ -2870,9 +2883,15 @@ static void refill_work(struct work_struct *work) > > for (i = 0; i < vi->curr_queue_pairs; i++) { > > struct receive_queue *rq = &vi->rq[i]; > > > > + rtnl_lock(); > > virtnet_napi_disable(rq); > > + rtnl_unlock(); > > + > > still_empty = !try_fill_recv(vi, rq, GFP_KERNEL); > > + > > + rtnl_lock(); > > virtnet_napi_enable(rq); > > + rtnl_unlock(); > > Looks to me like refill_work is cancelled _sync while holding rtnl_lock > from the close path. I think this could deadlock? Good catch, thank you! It looks like this is also the case in the failure path on virtnet_open. Jason: do you have any suggestions? It looks like in both open and close disable_delayed_refill is called first, before the cancel_delayed_work_sync. Would something like this solve the problem? diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 76dcd65ec0f2..457115300f05 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2880,6 +2880,13 @@ static void refill_work(struct work_struct *work) bool still_empty; int i; + spin_lock(&vi->refill_lock); + if (!vi->refill_enabled) { + spin_unlock(&vi->refill_lock); + return; + } + spin_unlock(&vi->refill_lock); + for (i = 0; i < vi->curr_queue_pairs; i++) { struct receive_queue *rq = &vi->rq[i];