From 4364d5f96eed7994a2c625bd9216656e55fba0cb Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 5 Jun 2013 15:40:46 +0800 Subject: vhost_net: clear msg.control for non-zerocopy case during tx When we decide not use zero-copy, msg.control should be set to NULL otherwise macvtap/tap may set zerocopy callbacks which may decrease the kref of ubufs wrongly. Bug were introduced by commit cedb9bdce099206290a2bdd02ce47a7b253b6a84 (vhost-net: skip head management if no outstanding). This solves the following warnings: WARNING: at include/linux/kref.h:47 handle_tx+0x477/0x4b0 [vhost_net]() Modules linked in: vhost_net macvtap macvlan tun nfsd exportfs bridge stp llc openvswitch kvm_amd kvm bnx2 megaraid_sas [last unloaded: tun] CPU: 5 PID: 8670 Comm: vhost-8668 Not tainted 3.10.0-rc2+ #1566 Hardware name: Dell Inc. PowerEdge R715/00XHKG, BIOS 1.5.2 04/19/2011 ffffffffa0198323 ffff88007c9ebd08 ffffffff81796b73 ffff88007c9ebd48 ffffffff8103d66b 000000007b773e20 ffff8800779f0000 ffff8800779f43f0 ffff8800779f8418 000000000000015c 0000000000000062 ffff88007c9ebd58 Call Trace: [] dump_stack+0x19/0x1e [] warn_slowpath_common+0x6b/0xa0 [] warn_slowpath_null+0x15/0x20 [] handle_tx+0x477/0x4b0 [vhost_net] [] handle_tx_kick+0x10/0x20 [vhost_net] [] vhost_worker+0xfe/0x1a0 [vhost_net] [] ? vhost_attach_cgroups_work+0x30/0x30 [vhost_net] [] ? vhost_attach_cgroups_work+0x30/0x30 [vhost_net] [] kthread+0xc6/0xd0 [] ? kthread_freezable_should_stop+0x70/0x70 [] ret_from_fork+0x7c/0xb0 [] ? kthread_freezable_should_stop+0x70/0x70 Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- drivers/vhost/net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/vhost') diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 2b51e23..b07d96b 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -436,7 +436,8 @@ static void handle_tx(struct vhost_net *net) kref_get(&ubufs->kref); } nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; - } + } else + msg.msg_control = NULL; /* TODO: Check specific error and bomb out unless ENOBUFS? */ err = sock->ops->sendmsg(NULL, sock, &msg, len); if (unlikely(err < 0)) { -- cgit v1.1 From 05c05351943cc03bf5c77e86953b24ae6fb21368 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 6 Jun 2013 15:20:39 +0300 Subject: vhost: check owner before we overwrite ubuf_info If device has an owner, we shouldn't touch ubuf_info since it might be in use. Signed-off-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- drivers/vhost/net.c | 4 ++++ drivers/vhost/vhost.c | 8 +++++++- drivers/vhost/vhost.h | 1 + 3 files changed, 12 insertions(+), 1 deletion(-) (limited to 'drivers/vhost') diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index b07d96b..8cf5aec 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -1054,6 +1054,10 @@ static long vhost_net_set_owner(struct vhost_net *n) int r; mutex_lock(&n->dev.mutex); + if (vhost_dev_has_owner(&n->dev)) { + r = -EBUSY; + goto out; + } r = vhost_net_set_ubuf_info(n); if (r) goto out; diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index beee7f5..60aa5ad 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -344,13 +344,19 @@ static int vhost_attach_cgroups(struct vhost_dev *dev) } /* Caller should have device mutex */ +bool vhost_dev_has_owner(struct vhost_dev *dev) +{ + return dev->mm; +} + +/* Caller should have device mutex */ long vhost_dev_set_owner(struct vhost_dev *dev) { struct task_struct *worker; int err; /* Is there an owner already? */ - if (dev->mm) { + if (vhost_dev_has_owner(dev)) { err = -EBUSY; goto err_mm; } diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index a7ad635..64adcf9 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -133,6 +133,7 @@ struct vhost_dev { long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs); long vhost_dev_set_owner(struct vhost_dev *dev); +bool vhost_dev_has_owner(struct vhost_dev *dev); long vhost_dev_check_owner(struct vhost_dev *); struct vhost_memory *vhost_dev_reset_owner_prepare(void); void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_memory *); -- cgit v1.1 From 288cfe78c8173f35c7a94f06859f60b3693d828a Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 6 Jun 2013 15:20:46 +0300 Subject: vhost: fix ubuf_info cleanup vhost_net_clear_ubuf_info didn't clear ubuf_info after kfree, this could trigger double free. Fix this and simplify this code to make it more robust: make sure ubuf info is always freed through vhost_net_clear_ubuf_info. Reported-by: Tommi Rantala Signed-off-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- drivers/vhost/net.c | 22 +++++++--------------- 1 file changed, 7 insertions(+), 15 deletions(-) (limited to 'drivers/vhost') diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 8cf5aec..f80d3dd 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -155,14 +155,11 @@ static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) static void vhost_net_clear_ubuf_info(struct vhost_net *n) { - - bool zcopy; int i; - for (i = 0; i < n->dev.nvqs; ++i) { - zcopy = vhost_net_zcopy_mask & (0x1 << i); - if (zcopy) - kfree(n->vqs[i].ubuf_info); + for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { + kfree(n->vqs[i].ubuf_info); + n->vqs[i].ubuf_info = NULL; } } @@ -171,7 +168,7 @@ int vhost_net_set_ubuf_info(struct vhost_net *n) bool zcopy; int i; - for (i = 0; i < n->dev.nvqs; ++i) { + for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { zcopy = vhost_net_zcopy_mask & (0x1 << i); if (!zcopy) continue; @@ -183,12 +180,7 @@ int vhost_net_set_ubuf_info(struct vhost_net *n) return 0; err: - while (i--) { - zcopy = vhost_net_zcopy_mask & (0x1 << i); - if (!zcopy) - continue; - kfree(n->vqs[i].ubuf_info); - } + vhost_net_clear_ubuf_info(n); return -ENOMEM; } @@ -196,12 +188,12 @@ void vhost_net_vq_reset(struct vhost_net *n) { int i; + vhost_net_clear_ubuf_info(n); + for (i = 0; i < VHOST_NET_VQ_MAX; i++) { n->vqs[i].done_idx = 0; n->vqs[i].upend_idx = 0; n->vqs[i].ubufs = NULL; - kfree(n->vqs[i].ubuf_info); - n->vqs[i].ubuf_info = NULL; n->vqs[i].vhost_hlen = 0; n->vqs[i].sock_hlen = 0; } -- cgit v1.1