Re: [PATCH rdma-next v2] RDMA/mlx5: Add missing error flow in mlx5_ib_set_vport_rep

[sashiko-bot@kernel.org]

> From: Shay Drory <shayd@nvidia.com>
> 
> mlx5_ib_set_vport_rep() attaches the representor netdev to the IB
> device, which takes a netdev reference, and then adds the LAG demux
> rule. If mlx5_lag_demux_rule_add() fails, the error is returned
> without detaching the netdev. The eswitch does not call unload() for a
> representor whose load() failed, so the reference is never dropped and
> a later unregister_netdevice() of the representor waits forever while
> holding the eswitch representors lock.
> 
> Add the demux rule before publishing the rep and attaching its netdev,
> so a failure there leaves nothing to undo. The rep pointers are still
> set before ib_device_set_netdev() sends the netdev attach event, so a
> listener never sees the attached port without its rep.
> 
> If ib_device_set_netdev() fails, delete the demux rule and clear the
> rep pointers. ib_device_set_netdev() cannot fail here, as the port
> index is always valid and the port data was allocated when the uplink
> rep was loaded, so clearing the pointers does not race with lockless
> readers.
> 
> Fixes: d6c9b4de8109 ("{net/RDMA}/mlx5: Add LAG demux table API and vport demux rules")
> Signed-off-by: Shay Drory <shayd@nvidia.com>
> Reviewed-by: Chiara Meiohas <cmeiohas@nvidia.com>
> Reviewed-by: Mark Bloch <mbloch@nvidia.com>
> Signed-off-by: Edward Srouji <edwards@nvidia.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261109-rep-netdev-leak-v2-1-9a6d164142e5@nvidia.com?part=1