From: Jason Wang Date: Mon, 26 Mar 2018 08:10:23 +0000 (+0800) Subject: vhost_net: add missing lock nesting notation X-Git-Tag: v4.15.17~2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=94f1b8485ce3e6fd0b736ae7c671838eaee2c21c;p=thirdparty%2Fkernel%2Fstable.git vhost_net: add missing lock nesting notation [ Upstream commit aaa3149bbee9ba9b4e6f0bd6e3e7d191edeae942 ] We try to hold TX virtqueue mutex in vhost_net_rx_peek_head_len() after RX virtqueue mutex is held in handle_rx(). This requires an appropriate lock nesting notation to calm down deadlock detector. Fixes: 0308813724606 ("vhost_net: basic polling support") Reported-by: syzbot+7f073540b1384a614e09@syzkaller.appspotmail.com Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 5636c7ca8ebac..0020ae906bf9c 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -618,7 +618,7 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk) if (!len && vq->busyloop_timeout) { /* Both tx vq and rx socket were polled here */ - mutex_lock(&vq->mutex); + mutex_lock_nested(&vq->mutex, 1); vhost_disable_notify(&net->dev, vq); preempt_disable(); @@ -751,7 +751,7 @@ static void handle_rx(struct vhost_net *net) struct iov_iter fixup; __virtio16 num_buffers; - mutex_lock(&vq->mutex); + mutex_lock_nested(&vq->mutex, 0); sock = vq->private_data; if (!sock) goto out;