Re: [PATCH net 1/2] dibs: loopback: reset the client id when the owner unregisters a DMB

[sashiko-bot@kernel.org]

> From: Bryam Vargas <hexlabsecurity@proton.me>
> 
> dibs_lo_unregister_dmb() resets the DMB's dmb_clientid_arr[] entry only
> on the last put. If an attacher still holds the DMB, as when an SMC link
> group is freed while a peer is still attached, the entry stays set after
> the attacher's dibs_lo_detach_dmb() frees the DMB.
> dibs_unregister_client() then warns at rmmod smc and returns -EBUSY,
> which smc_ism_exit() ignores: smc stays in clients[] and dibs->subs[],
> and a later dibs_dev_add() or dibs_dev_del() (rmmod dibs, ISM hotplug)
> calls into the unloaded module.
> 
> Reset the entry when the owner unregisters, before its put, as
> ism_unregister_dmb() does. The index stays allocated until the last put,
> and the attacher's writes no longer raise an interrupt for a client that
> gave the DMB up.
> 
> Fixes: cc21191b584c ("dibs: Move data path to dibs layer")
> Cc: stable@vger.kernel.org
> Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>

Sashiko has reviewed this patch and found no issues.

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