From 579cd6fe1e70cdba651eeac567df3ad0dc2272ad Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Mon, 26 Mar 2018 16:10:23 +0800 Subject: [PATCH] UPSTREAM: 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 (cherry picked from commit 1cb81756b7c3813f7d65d3c6bb1133cb53b69775) Bug: 121166534 Test: Ran cuttlefish with android-4.4 + VSOCKETS, VMWARE_VMCI_VSOCKETS Signed-off-by: Alistair Strachan Change-Id: Ia72badca8f5f92095cfad91051fe47f76e6b03b7 --- drivers/vhost/net.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 4b3cae02c0dc..53cf130922f3 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -510,7 +510,7 @@ 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(); @@ -643,7 +643,7 @@ 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;