> -----Original Message-----
> From: Saurabh Sengar <ssen...@linux.microsoft.com>
> Sent: Saturday, May 17, 2025 11:48 PM
> To: KY Srinivasan <k...@microsoft.com>; Haiyang Zhang
> <haiya...@microsoft.com>; wei....@kernel.org; Dexuan Cui
> <de...@microsoft.com>; andrew+net...@lunn.ch; da...@davemloft.net;
> eduma...@google.com; pab...@redhat.com; ho...@kernel.org; a...@kernel.org;
> dan...@iogearbox.net; h...@kernel.org; john.fastab...@gmail.com;
> s...@fomichev.me; kun...@amazon.com; ahmed.z...@intel.com;
> aleksander.loba...@intel.com; linux-hyperv@vger.kernel.org;
> net...@vger.kernel.org; linux-ker...@vger.kernel.org; b...@vger.kernel.org
> Cc: Saurabh Singh Sengar <ssen...@microsoft.com>; sta...@vger.kernel.org;
> Saurabh Sengar <ssen...@linux.microsoft.com>
> Subject: [PATCH net] hv_netvsc: fix potential deadlock in
> netvsc_vf_setxdp()
>
> 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>
Reviewed-by: Haiyang Zhang <haiya...@microsoft.com>
