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hv_netvsc: fix potential deadlock in netvsc_vf_setxdp()

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The MANA driver's probe registers netdevice via the following call chain:

mana_probe()
  register_netdev()
    register_netdevice()

register_netdevice() calls notifier callback for netvsc driver,
holding the netdev mutex via netdev_lock_ops().

Further this netvsc notifier callback end up attempting to acquire the
same lock again in dev_xdp_propagate() leading to deadlock.

netvsc_netdev_event()
  netvsc_vf_setxdp()
    dev_xdp_propagate()

This deadlock was not observed so far because net_shaper_ops was never set,
and thus the lock was effectively a no-op in this case. Fix this by using
netif_xdp_propagate() instead of dev_xdp_propagate() to avoid recursive
locking in this path.

And, since no deadlock is observed on the other path which is via
netvsc_probe, add the lock exclusivly for that path.

Also, clean up the unregistration path by removing the unnecessary call to
netvsc_vf_setxdp(), since unregister_netdevice_many_notify() already
performs this cleanup via dev_xdp_uninstall().

Fixes: 97246d6d21 ("net: hold netdev instance lock during ndo_bpf")
Cc: stable@vger.kernel.org
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Tested-by: Erni Sri Satya Vennela <ernis@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Subbaraya Sundeep <sbhatta@marvell.com>
Link: https://patch.msgid.link/1748513910-23963-1-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Saurabh Sengar
2025-05-29 03:18:30 -07:00
committed by Jakub Kicinski
parent c1f4cb8a8d
commit 3ec5233049
3 changed files with 4 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/net/hyperv/netvsc_bpf.c
View File

@@ -183,7 +183,7 @@ int netvsc_vf_setxdp(struct net_device *vf_netdev, struct bpf_prog *prog)
xdp.command = XDP_SETUP_PROG;
xdp.prog = prog;
ret = dev_xdp_propagate(vf_netdev, &xdp);
ret = netif_xdp_propagate(vf_netdev, &xdp);
if (ret && prog)
bpf_prog_put(prog);

4
drivers/net/hyperv/netvsc_drv.c
View File

@@ -2462,8 +2462,6 @@ static int netvsc_unregister_vf(struct net_device *vf_netdev)
netdev_info(ndev, "VF unregistering: %s\n", vf_netdev->name);
netvsc_vf_setxdp(vf_netdev, NULL);
reinit_completion(&net_device_ctx->vf_add);
netdev_rx_handler_unregister(vf_netdev);
netdev_upper_dev_unlink(vf_netdev, ndev);
@@ -2631,7 +2629,9 @@ static int netvsc_probe(struct hv_device *dev,
continue;
netvsc_prepare_bonding(vf_netdev);
netdev_lock_ops(vf_netdev);
netvsc_register_vf(vf_netdev, VF_REG_IN_PROBE);
netdev_unlock_ops(vf_netdev);
__netvsc_vf_setup(net, vf_netdev);
break;
}

1
net/core/dev.c
View File

@@ -9968,6 +9968,7 @@ int netif_xdp_propagate(struct net_device *dev, struct netdev_bpf *bpf)
return dev->netdev_ops->ndo_bpf(dev, bpf);
}
EXPORT_SYMBOL_GPL(netif_xdp_propagate);
u32 dev_xdp_prog_id(struct net_device *dev, enum bpf_xdp_mode mode)
{