On Sat, May 17, 2025 at 08:47:50PM -0700, Saurabh Sengar wrote:
> 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: [email protected]
> Signed-off-by: Saurabh Sengar <[email protected]>
> ---
Built and booted successfully.
Tested-by: Erni Sri Satya Vennela <[email protected]>
Thanks!
