From patchwork Tue Jan 30 10:16:12 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Souradeep Chakrabarti X-Patchwork-Id: 13537179 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 82C9F605B4; Tue, 30 Jan 2024 10:16:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706609780; cv=none; b=BZeeDWrWw90crDzB/7gkEUxvK3bXsB3oxq3fteLEB7NScpShlbzLZmlAi2gwg6ANDpK/4lHOSE9tjebXIyTe7+lI3hQwg5kQ/tlCL7ttaHaRXXlwxac3mldz7cVLuD7dYOPR7gZW7TSGTCKjAPCfHCkxOcgMtlZPLErP2f3dYO8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706609780; c=relaxed/simple; bh=EKido4cfkiPSNL005kSWWswMbAIta1D446sWSq/aX7s=; h=From:To:Cc:Subject:Date:Message-Id; b=VvGm7zfonclBXn8maCGhqIrFck2gTm/aubYWuhEJYTXU4PPuk9uCYx/f8ynVeNZ7GUNuw0D1WAn+dX6fwpi4OxuRYOTGsL/GoQ6K0jBHyhSXqcPpQ85T9lVoCb3YcpnhX+vu+3KUg5MkJjHmFhCwyX6PMxmfo15wjj8NvrriFw0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=EOXJFH0G; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="EOXJFH0G" Received: by linux.microsoft.com (Postfix, from userid 1099) id 0489720541E2; Tue, 30 Jan 2024 02:16:18 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 0489720541E2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1706609778; bh=lWjvTitWSXmCVj9tD67yPr16D3fiYZ1z5BKjD2XlLRg=; h=From:To:Cc:Subject:Date:From; b=EOXJFH0G7tayi52lb6OIV4X8MfQM5rdbWzzN8htV351zOxwFxrJGx4Gh9m0I4lhpz gi33oSm245JV5oWwlD11Eo2pd3O5Dauj5ZPPwRNu5kJ+IaSLeTGjDnsfDlNljn4Il5 PUlNQmoTnNJvmpKmPEeeXGIwvdCqEfLvdH5SkqbU= From: Souradeep Chakrabarti To: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, longli@microsoft.com, yury.norov@gmail.com, leon@kernel.org, cai.huoqing@linux.dev, ssengar@linux.microsoft.com, vkuznets@redhat.com, tglx@linutronix.de, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org Cc: schakrabarti@microsoft.com, Souradeep Chakrabarti Subject: [PATCH net] hv_netvsc: Fix race condition between netvsc_probe and netvsc_remove Date: Tue, 30 Jan 2024 02:16:12 -0800 Message-Id: <1706609772-5783-1-git-send-email-schakrabarti@linux.microsoft.com> X-Mailer: git-send-email 1.8.3.1 Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: In commit ac5047671758 ("hv_netvsc: Disable NAPI before closing the VMBus channel"), napi_disable was getting called for all channels, including all subchannels without confirming if they are enabled or not. Which caused hv_netvsc getting hung at napi_disable, when netvsc_probe() and netvsc_remove() are happening simultaneously and netvsc_remove() calls cancel_work_sync(&nvdev->subchan_work) before netvsc_sc_open() calls napi_enable for the sub channels. Which causes NAPIF_STATE_SCHED bit not getting cleared for the subchannels. Now during netvsc_device_remove(), when napi_disable is called for those subchannels, napi_disable gets stuck on infinite msleep. Call trace: [ 654.559417] task:modprobe state:D stack: 0 pid: 2321 ppid: 1091 flags:0x00004002 [ 654.568030] Call Trace: [ 654.571221] [ 654.573790] __schedule+0x2d6/0x960 [ 654.577733] schedule+0x69/0xf0 [ 654.581214] schedule_timeout+0x87/0x140 [ 654.585463] ? __bpf_trace_tick_stop+0x20/0x20 [ 654.590291] msleep+0x2d/0x40 [ 654.593625] napi_disable+0x2b/0x80 [ 654.597437] netvsc_device_remove+0x8a/0x1f0 [hv_netvsc] [ 654.603935] rndis_filter_device_remove+0x194/0x1c0 [hv_netvsc] [ 654.611101] ? do_wait_intr+0xb0/0xb0 [ 654.615753] netvsc_remove+0x7c/0x120 [hv_netvsc] [ 654.621675] vmbus_remove+0x27/0x40 [hv_vmbus] Fixes: ac5047671758 ("hv_netvsc: Disable NAPI before closing the VMBus channel") Signed-off-by: Souradeep Chakrabarti Reviewed-by: Haiyang Zhang Reviewed-by: Dexuan Cui --- drivers/net/hyperv/netvsc.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index 1dafa44155d0..a6fcbda64ecc 100644 --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -708,7 +708,10 @@ void netvsc_device_remove(struct hv_device *device) /* Disable NAPI and disassociate its context from the device. */ for (i = 0; i < net_device->num_chn; i++) { /* See also vmbus_reset_channel_cb(). */ - napi_disable(&net_device->chan_table[i].napi); + /* only disable enabled NAPI channel */ + if (i < ndev->real_num_rx_queues) + napi_disable(&net_device->chan_table[i].napi); + netif_napi_del(&net_device->chan_table[i].napi); }