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| author |   Ilya Maximets <i.maximets@samsung.com> | 2019-07-08 14:03:44 +0300 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2019-07-12 15:02:21 +0200 |
| commit | 5464c3a0e9a037b63d5229cdea08dddc01a98aac (patch) | |
| tree | b7d54d9aef6b6e95b7db08ad745aa5345b4a856f /net/xdp/xdp_umem.c | |
| parent | xdp: fix possible cq entry leak (diff) | |
| download | linux-dev-5464c3a0e9a037b63d5229cdea08dddc01a98aac.tar.xz linux-dev-5464c3a0e9a037b63d5229cdea08dddc01a98aac.zip | |
xdp: fix potential deadlock on socket mutex
There are 2 call chains:
a) xsk_bind --> xdp_umem_assign_dev
b) unregister_netdevice_queue --> xsk_notifier
with the following locking order:
a) xs->mutex --> rtnl_lock
b) rtnl_lock --> xdp.lock --> xs->mutex
Different order of taking 'xs->mutex' and 'rtnl_lock' could produce a
deadlock here. Fix that by moving the 'rtnl_lock' before 'xs->lock' in
the bind call chain (a).
Reported-by: syzbot+bf64ec93de836d7f4c2c@syzkaller.appspotmail.com
Fixes: 455302d1c9ae ("xdp: fix hang while unregistering device bound to xdp socket")
Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'net/xdp/xdp_umem.c')
| -rw-r--r-- | net/xdp/xdp_umem.c | 16 |
1 files changed, 6 insertions, 10 deletions
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c index 20c91f02d3d8..83de74ca729a 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -87,21 +87,20 @@ int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev, struct netdev_bpf bpf; int err = 0; + ASSERT_RTNL(); + force_zc = flags & XDP_ZEROCOPY; force_copy = flags & XDP_COPY; if (force_zc && force_copy) return -EINVAL; - rtnl_lock(); - if (xdp_get_umem_from_qid(dev, queue_id)) { - err = -EBUSY; - goto out_rtnl_unlock; - } + if (xdp_get_umem_from_qid(dev, queue_id)) + return -EBUSY; err = xdp_reg_umem_at_qid(dev, umem, queue_id); if (err) - goto out_rtnl_unlock; + return err; umem->dev = dev; umem->queue_id = queue_id; @@ -110,7 +109,7 @@ int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev, if (force_copy) /* For copy-mode, we are done. */ - goto out_rtnl_unlock; + return 0; if (!dev->netdev_ops->ndo_bpf || !dev->netdev_ops->ndo_xsk_async_xmit) { @@ -125,7 +124,6 @@ int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev, err = dev->netdev_ops->ndo_bpf(dev, &bpf); if (err) goto err_unreg_umem; - rtnl_unlock(); umem->zc = true; return 0; @@ -135,8 +133,6 @@ err_unreg_umem: err = 0; /* fallback to copy mode */ if (err) xdp_clear_umem_at_qid(dev, queue_id); -out_rtnl_unlock: - rtnl_unlock(); return err; } |