Re: [RFC PATCH 6.6.y] xprtrdma: Fix endpoint leak after address change and device removal

[sashiko-bot@kernel.org]

> Commit a562485c359d ("xprtrdma: Fix ep kref imbalance on ADDR_CHANGE")
> is the linux-6.6.y backport of af9b65b29af34. It leaves the ESTABLISHED
> reference outstanding after ADDR_CHANGE and relies on a subsequent
> DISCONNECTED event to release it.
> 
> However, linux-6.6.y still handles DEVICE_REMOVAL in the CM event
> handler. Consider the following sequence on an established connection:
> 
>   ESTABLISHED:    acquire the connection reference, status = 1
>   ADDR_CHANGE:    set status = -ENODEV and request asynchronous close
>   DEVICE_REMOVAL: observe status = -ENODEV, skip the disconnected path
> 
> Before invoking the DEVICE_REMOVAL callback, the CMA sets the CM ID state
> to RDMA_CM_DEVICE_REMOVAL. cma_ib_handler() then filters subsequent
> IB CM disconnect events. The DEVICE_REMOVAL handler has skipped the
> [ ... ]
> The flag is initially clear in the zero-initialized endpoint, and
> all accesses are serialized by the CM ID's handler mutex.
> 
> Fixes: a562485c359d ("xprtrdma: Fix ep kref imbalance on ADDR_CHANGE")
> Signed-off-by: Li Xiasong <lixiasong1@huawei.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261105124224.4051975-1-lixiasong1@huawei.com?part=1