From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (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 AC9F625B1DA for ; Fri, 2 Jan 2026 15:20:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767367245; cv=none; b=RtB7YVLNsw6TtgThetQ+RWccMiRa6RkvLVkjwhoAkUqSLxhGSNOwk8zxxAaC8LDrMchSqzDhWt5IlW682RxinQxI+gEwOmc/a/H+y2kZFsus2WxM7rvDr+4RGdScwzDkcMTxhTsfJ7dOJPHRaJA43KfbQXVj+tp1Uhv5x6yu8aQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767367245; c=relaxed/simple; bh=bEfI9VdyBfyGoJu/InKuPX/XT/uFeqFxXXZCS+SC1Mc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Z4vf/LnqaWZron2PDro2nVkaUxEPXSuDQ2DqatvIVScvx6YRxPtYtjgfFwvGKLW1cVqeKcPAAOHwbQzj4Mf1AuyPmSoJ3iHQkswxIdpUPg5tXSMgUVY5fZPOeySCFEqzZEtAury0zjuASW9bQb7IuBwX8G6m7DaOd3XAWksWG+Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=LPxmJ7EZ; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="LPxmJ7EZ" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-29f2676bb21so167833185ad.0 for ; Fri, 02 Jan 2026 07:20:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1767367243; x=1767972043; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=4w30MU9We+VQZj/AlvgZCJU00iqT1dGAHAA+FFNT8Fc=; b=LPxmJ7EZSxyn0N9JalSZFqsmiWvfbF9PvA06JZqPjEiuD14+NGohm4zyVYKnXAtH3u kFPD3mxVxTv44vCizwO42ZtmsieRT31DhMNejzRf97iuf8DuQ4K1216MQDfJ8H8BeQnx sehoQtpySQzQ6giZ8yGVebt/HHMtlwJgdO+KWRdxXdxu2fh057ozNdzdUXTnlQPEEeVs MmQLeS023u69900tECYJlyR6iPnrsORk/eJUTM7ZL+VhC1/S2JZsZfgTXd1GmERo6zsb 82P0FWlIjRZWAoRah7SQ+ZlFtMciaMahIaeIlDOdViIYfnaE9XaYZTJ6kN4P23+cP+U4 h9xQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767367243; x=1767972043; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=4w30MU9We+VQZj/AlvgZCJU00iqT1dGAHAA+FFNT8Fc=; b=vgLFvL/dCXFbuqLgdYz0e54vrh0fS5ErUXuD9fuHZAfOsoVotNvn5g1+4ri9nfzT/1 1HKysSCBPIV+/SJ3dEfT/GSjPKaJo7dPtXUS4OeDU6nOY0dZmT7QBwU0pgijURi3z6zH 2RI6JHRYyp6OsFWxtkPzNZeg1m/I2fokKphZ0Kb+oEAXW60wF0K5S5pL3UydSRXGLzmv E7vv9+AvpVJHy3IFbj0CJAXk2Xrljee1MZnLFD8nLyfG3ie34hTcSO+gfuuUEl3Myyoh GeNUDo1hsxjae4DEvS7z77pnMF5oBC+bphtwwRrbhcaHnFPnxIc5gWibzMzcbylzYyrP AY5g== X-Forwarded-Encrypted: i=1; AJvYcCV8J7YkG8QizUrTaH+W9s8ulGygvpIAQKmNegZzLX7bEhdmgFb1Huum2Kk+XBcaFlywEaYX75DbUqyh0Ng=@vger.kernel.org X-Gm-Message-State: AOJu0YwXzvHv8WqqsufnzPKuT0etnuU7H+EacxK+1/BQXc5u+i3I4rac SoFAuGPJXljZd8dhWFhyz2hNXzwkQbSOWoicNn1R2NABljuao4k/NJ7h X-Gm-Gg: AY/fxX6B5lADEtvmLZ908GdqEk+5UEnYFE6bN57y6bpvME062r8s7alPnypvedWiONf TBw/EzRmd0KeB6r9zrj69Unv6UoxPBA8tADAAvSp7rMpw/GsP/lfnkQnI4Ygy1o/Fy5HdVipk7u iC0Wd2pdmQdD2KEWu3S6v6isFJFD3dDP9V/QZ3Qw7PDrhv5X+DzFZ6roJwrw6h51HD4bNy72KtD JXfCgB9TUDrB/3GDbbDPWj1LZn/1X1vEZ4jfcop4eMlPcfyGxPanpAMIoOwbTl3m2CK9SyATjB0 ph3U57sl1VT/2oUsY93cKgo9yZUIzs6/mI4H6aKg4AEzbKiQD0/fYgSD1ERnI6fPwPSsb8wcO9P EpQs/nRa11CvrwWw9jHDgQ7TnBCSx0iLC1Ir/fXPKgm8c9FJnloipgGEbb/S3XJ4aD5gKMoDzbO ros1In2paskbZFfZgZRRoceZY= X-Google-Smtp-Source: AGHT+IFMmIn+2/J2pbEHZ9vcoQ6zTgkAbud3TeSk4TfYXDj4qwzEgISl47tpMlZjJUNUzJ74kzK3hA== X-Received: by 2002:a17:902:d4c7:b0:2a0:d7f6:e030 with SMTP id d9443c01a7336-2a2f2836757mr413049005ad.29.1767367242912; Fri, 02 Jan 2026 07:20:42 -0800 (PST) Received: from minh.192.168.1.1 ([2001:ee0:4f4c:210:a612:725:7af0:96ca]) by smtp.googlemail.com with ESMTPSA id 41be03b00d2f7-c1e7c146aabsm35041268a12.25.2026.01.02.07.20.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Jan 2026 07:20:42 -0800 (PST) From: Bui Quang Minh To: netdev@vger.kernel.org Cc: "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Stanislav Fomichev , virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, Bui Quang Minh Subject: [PATCH net v2 0/3] virtio-net: fix the deadlock when disabling rx NAPI Date: Fri, 2 Jan 2026 22:20:20 +0700 Message-ID: <20260102152023.10773-1-minhquangbui99@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Calling napi_disable() on an already disabled napi can cause the deadlock. In commit 4bc12818b363 ("virtio-net: disable delayed refill when pausing rx"), to avoid the deadlock, when pausing the RX in virtnet_rx_pause[_all](), we disable and cancel the delayed refill work. However, in the virtnet_rx_resume_all(), we enable the delayed refill work too early before enabling all the receive queue napis. The deadlock can be reproduced by running selftests/drivers/net/hw/xsk_reconfig.py with multiqueue virtio-net device and inserting a cond_resched() inside the for loop in virtnet_rx_resume_all() to increase the success rate. Because the worker processing the delayed refilled work runs on the same CPU as virtnet_rx_resume_all(), a reschedule is needed to cause the deadlock. In real scenario, the contention on netdev_lock can cause the reschedule. Due to the complexity of delayed refill worker, in this series, we remove it. When we fail to refill the receive buffer, we will retry in the next NAPI poll instead. - Patch 1: removes delayed refill worker schedule and retry refill in next NAPI - Patch 2, 3: removes and clean up unused delayed refill worker code For testing, I've run the following tests with no issue so far - selftests/drivers/net/hw/xsk_reconfig.py which sets up the XDP zerocopy without providing any descriptors to the fill ring. As a result, try_fill_recv will always fail. - Send TCP packets from host to guest while guest is nearly OOM and some try_fill_recv calls fail. Changes in v2: - Remove the delayed refill worker to simplify the logic instead of trying to fix it - Link to v1: https://lore.kernel.org/netdev/20251223152533.24364-1-minhquangbui99@gmail.com/ Link to the previous approach and discussion: https://lore.kernel.org/netdev/20251212152741.11656-1-minhquangbui99@gmail.com/ Thanks, Quang Minh. Bui Quang Minh (3): virtio-net: don't schedule delayed refill worker virtio-net: remove unused delayed refill worker virtio-net: clean up __virtnet_rx_pause/resume drivers/net/virtio_net.c | 171 +++++++++------------------------------ 1 file changed, 40 insertions(+), 131 deletions(-) -- 2.43.0