Re: drivers/vhost/net.c:1010 vhost_net_rx_peek_head_len() error: double unlocked 'sk->sk_receive_queue.lock' (orig line 1002)
From: Michael S. Tsirkin
Date: Mon Aug 10 2020 - 08:34:06 EST
On Sat, Aug 08, 2020 at 03:37:07PM +0800, kernel test robot wrote:
> Hi Jason,
>
> First bad commit (maybe != root cause):
>
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: 449dc8c97089a6e09fb2dac4d92b1b7ac0eb7c1e
> commit: 20c384f1ea1a0bc7320bc445c72dd02d2970d594 vhost: refine vhost and vringh kconfig
> date: 4 months ago
> config: arm-randconfig-m031-20200808 (attached as .config)
> compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>
> New smatch warnings:
> drivers/vhost/net.c:1010 vhost_net_rx_peek_head_len() error: double unlocked 'sk->sk_receive_queue.lock' (orig line 1002)
> drivers/vhost/net.c:1010 vhost_net_rx_peek_head_len() error: double unlocked 'sk->sk_receive_queue.lock' (orig line 1002)
Weird. Can't figure out where the double unlock is ...
> Old smatch warnings:
> drivers/vhost/net.c:1528 vhost_net_set_backend() warn: passing a valid pointer to 'PTR_ERR'
this stumped me too...
> vim +1010 drivers/vhost/net.c
>
> 8dd014adfea6f17 David Stevens 2010-07-27 994
> be294a51adfc1e1 Toshiaki Makita 2018-07-03 995 static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk,
> be294a51adfc1e1 Toshiaki Makita 2018-07-03 996 bool *busyloop_intr)
> 030881372460654 Jason Wang 2016-03-04 997 {
> 28b9b33b983f4de Toshiaki Makita 2018-07-03 998 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX];
> 28b9b33b983f4de Toshiaki Makita 2018-07-03 999 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX];
> 6369fec5be0aad4 Toshiaki Makita 2018-07-03 1000 struct vhost_virtqueue *rvq = &rnvq->vq;
> 28b9b33b983f4de Toshiaki Makita 2018-07-03 1001 struct vhost_virtqueue *tvq = &tnvq->vq;
> 28b9b33b983f4de Toshiaki Makita 2018-07-03 @1002 int len = peek_head_len(rnvq, sk);
> 030881372460654 Jason Wang 2016-03-04 1003
> dc151282bbdaed0 Tonghao Zhang 2018-09-25 1004 if (!len && rvq->busyloop_timeout) {
> f5a4941aa6d190e Jason Wang 2018-05-29 1005 /* Flush batched heads first */
> 09c3248938c3e3b Jason Wang 2018-07-20 1006 vhost_net_signal_used(rnvq);
> 030881372460654 Jason Wang 2016-03-04 1007 /* Both tx vq and rx socket were polled here */
> dc151282bbdaed0 Tonghao Zhang 2018-09-25 1008 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true);
> 030881372460654 Jason Wang 2016-03-04 1009
> 28b9b33b983f4de Toshiaki Makita 2018-07-03 @1010 len = peek_head_len(rnvq, sk);
> 030881372460654 Jason Wang 2016-03-04 1011 }
> 030881372460654 Jason Wang 2016-03-04 1012
> 030881372460654 Jason Wang 2016-03-04 1013 return len;
> 030881372460654 Jason Wang 2016-03-04 1014 }
> 030881372460654 Jason Wang 2016-03-04 1015
>
> :::::: The code at line 1010 was first introduced by commit
> :::::: 28b9b33b983f4de3ce9e660e3efe1e08adabf779 vhost_net: Rename local variables in vhost_net_rx_peek_head_len
>
> :::::: TO: Toshiaki Makita <makita.toshiaki@xxxxxxxxxxxxx>
> :::::: CC: David S. Miller <davem@xxxxxxxxxxxxx>
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx