From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1358E446C9; Tue, 20 Feb 2024 21:37:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708465035; cv=none; b=oOT7QRwPqkuSVZJyx/VB6FgV8ojp1YtuqpZbow4Q43TlDuAMgt2+MpNDxG7OpvLfTn8DnCeqm6OsCGodQ8j/glPJlc1L0gZ+IzwVOqbXQgTaHhdmMJMFUqinGpAqCxYzQyRSSAl9wok7orqQh+hWCJiZ2Wxw5l6RvcdxAorHBZE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708465035; c=relaxed/simple; bh=yQuMN+X1pnPhDItFXMkAl8jY8ew4Sa8bb9ukPQdu3nk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cyU6aY/vyc2jbpy0X2v8tVLiZmkeAbZjUnvyKjoRg97a+UFUW09QeGiq2OCB4N15DvUYuPz6cY0TUrNu8u5vXHUdZ31JbXm2PgGPZUcqOKTq+7eSiu2LW4EMlsq5dUwRfvI9iQZJ/mE5PAyYB+QeQKrl/TK/evCgH0mq+iMGATc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hkq/CUUX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hkq/CUUX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C14FC433C7; Tue, 20 Feb 2024 21:37:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1708465034; bh=yQuMN+X1pnPhDItFXMkAl8jY8ew4Sa8bb9ukPQdu3nk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hkq/CUUXqM8Kv+bc8wGxZHN1LQuhiNJiBZMUQSi4mpNMym0hwNJebPUYIH+s632T1 Mxer/gp1gE7uGhEskMFSI7uocFYX8XfPPCxZHOe++Ggb3muh9b7aG2NxRRXPBDZ6ke /nhD7MdqWJR9xptyDQNqhNFvKFzYGcrzxvWXFjEs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Souradeep Chakrabarti , Dexuan Cui , Haiyang Zhang , Simon Horman , Jakub Kicinski Subject: [PATCH 6.7 215/309] hv_netvsc: Fix race condition between netvsc_probe and netvsc_remove Date: Tue, 20 Feb 2024 21:56:14 +0100 Message-ID: <20240220205639.898723082@linuxfoundation.org> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240220205633.096363225@linuxfoundation.org> References: <20240220205633.096363225@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Souradeep Chakrabarti commit e0526ec5360a48ad3ab2e26e802b0532302a7e11 upstream. 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. This caused hv_netvsc getting hung at napi_disable, when netvsc_probe() has finished running but nvdev->subchan_work has not started yet. netvsc_subchan_work() -> rndis_set_subchannel() has not created the sub-channels and because of that netvsc_sc_open() is not running. netvsc_remove() calls cancel_work_sync(&nvdev->subchan_work), for which netvsc_subchan_work did not run. netif_napi_add() sets the bit NAPI_STATE_SCHED because it ensures NAPI cannot be scheduled. Then netvsc_sc_open() -> napi_enable will clear the NAPIF_STATE_SCHED bit, so it can be scheduled. napi_disable() does the opposite. Now during netvsc_device_remove(), when napi_disable is called for those subchannels, napi_disable gets stuck on infinite msleep. This fix addresses this problem by ensuring that napi_disable() is not getting called for non-enabled NAPI struct. But netif_napi_del() is still necessary for these non-enabled NAPI struct for cleanup purpose. 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] Cc: stable@vger.kernel.org Fixes: ac5047671758 ("hv_netvsc: Disable NAPI before closing the VMBus channel") Signed-off-by: Souradeep Chakrabarti Reviewed-by: Dexuan Cui Reviewed-by: Haiyang Zhang Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/1706686551-28510-1-git-send-email-schakrabarti@linux.microsoft.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/hyperv/netvsc.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -708,7 +708,10 @@ void netvsc_device_remove(struct hv_devi /* 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); }