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 this lock in noop in this case. Fix this by using
netif_xdp_propagate instead of dev_xdp_propagate to avoid recursive
locking in this path.
This issue has not observed so far because net_shaper_ops was unset,
making the lock path effectively a no-op. To prevent recursive locking
and avoid this deadlock, replace dev_xdp_propagate() with
netif_xdp_propagate(), which does not acquire the lock again.
Also, clean up the unregistration path by removing unnecessary call to
netvsc_vf_setxdp(), since unregister_netdevice_many_notify() already
performs this cleanup via dev_xdp_uninstall.
Fixes: 97246d6d21c2 ("net: hold netdev instance lock during ndo_bpf")
Cc: sta...@vger.kernel.org
Signed-off-by: Saurabh Sengar <ssen...@linux.microsoft.com>
---
drivers/net/hyperv/netvsc_bpf.c | 2 +-
drivers/net/hyperv/netvsc_drv.c | 2 --
net/core/dev.c | 1 +
3 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/net/hyperv/netvsc_bpf.c b/drivers/net/hyperv/netvsc_bpf.c
index e01c5997a551..1dd3755d9e6d 100644
--- a/drivers/net/hyperv/netvsc_bpf.c
+++ b/drivers/net/hyperv/netvsc_bpf.c
@@ -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);
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index d8b169ac0343..ee3aaf9c10e6 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -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);
diff --git a/net/core/dev.c b/net/core/dev.c
index fccf2167b235..8c6c9d7fba26 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9953,6 +9953,7 @@ 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)
{
--
2.43.0
