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From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: Ilya Maximets <i.maximets@samsung.com>
Cc: dev@dpdk.org, Huawei Xie <huawei.xie@intel.com>,
	Dyasly Sergey <s.dyasly@samsung.com>,
	Heetae Ahn <heetae82.ahn@samsung.com>,
	Thomas Monjalon <thomas.monjalon@6wind.com>
Subject: Re: [PATCH] vhost: fix connect hang in client mode
Date: Thu, 21 Jul 2016 17:37:14 +0800	[thread overview]
Message-ID: <20160721093714.GD28708@yliu-dev.sh.intel.com> (raw)
In-Reply-To: <1469089275-15209-1-git-send-email-i.maximets@samsung.com>

On Thu, Jul 21, 2016 at 11:21:15AM +0300, Ilya Maximets wrote:
> If something abnormal happened to QEMU, 'connect()' can block calling
> thread (e.g. main thread of OVS) forever or for a really long time.
> This can break whole application or block the reconnection thread.
> 
> Example with OVS:
> 
> 	ovs_rcu(urcu2)|WARN|blocked 512000 ms waiting for main to quiesce
> 	(gdb) bt
> 	#0  connect () from /lib64/libpthread.so.0
> 	#1  vhost_user_create_client (vsocket=0xa816e0)
> 	#2  rte_vhost_driver_register
> 	#3  netdev_dpdk_vhost_user_construct
> 	#4  netdev_open (name=0xa664b0 "vhost1")
> 	[...]
> 	#11 main
> 
> Fix that by setting non-blocking mode for client sockets for connection.
> 
> Fixes: 64ab701c3d1e ("vhost: add vhost-user client mode")

Thanks for spotting and fixing yet another bug!

>  
> +static int
> +vhost_user_connect_nonblock(int fd, struct sockaddr *un, size_t sz)

I don't quite understand why this is needed: connect() with O_NONBLOCK
flag set is not enough?

	--yliu

  reply	other threads:[~2016-07-21  9:33 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-21  8:21 [PATCH] vhost: fix connect hang in client mode Ilya Maximets
2016-07-21  9:37 ` Yuanhan Liu [this message]
2016-07-21  9:45   ` Ilya Maximets
2016-07-21 10:13     ` Yuanhan Liu
2016-07-21 10:37       ` Ilya Maximets
2016-07-21 11:14         ` Ilya Maximets
2016-07-21 11:40           ` Yuanhan Liu
2016-07-21 12:10             ` Ilya Maximets
2016-07-21 12:13               ` Ilya Maximets
2016-07-21 12:35                 ` Yuanhan Liu
2016-07-21 12:42                   ` Ilya Maximets
2016-07-21 12:58                     ` Yuanhan Liu
2016-07-21 12:58                       ` Ilya Maximets
2016-07-21 13:10                         ` Yuanhan Liu
2016-07-21 11:12 ` [PATCH v2] " Ilya Maximets
2016-07-21 13:19 ` [PATCH v3] " Ilya Maximets
2016-07-21 13:35   ` Yuanhan Liu
2016-07-21 13:43     ` Ilya Maximets
2016-07-21 13:56       ` Yuanhan Liu
2016-07-21 22:21     ` Thomas Monjalon

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