Re: [PATCH net] dibs: fix use-after-free of dmb_node in loopback attach/detach/unregister

Alexandra Winter <[email protected]> Wed, 29 Jul 2026 14:25:12 +0200
Newsgroups org.kernel.vger.linux-rdma,org.kernel.vger.linux-kernel,org.kernel.vger.linux-s390,org.kernel.vger.netdev
Message-ID <[email protected]>

On 27.07.26 11:35, Hidayath Khan wrote:
> dibs_lo_attach_dmb(), dibs_lo_detach_dmb() and dibs_lo_unregister_dmb()
> look up the dmb_node under dmb_ht_lock, drop the lock and only then
> operate on the node's refcount. Nothing keeps the node alive across
> that window: __dibs_lo_unregister_dmb() removes the node from the hash
> table under the write lock and immediately frees it.
> 

I had lost track of this, but Rahul Chandelkar had already proposed a
similar patch [1] for this issue, but never followed up with a v2.

Rahul, Hidayath,
Would it be ok for both of you to add
Reported-by: Rahul Chandelkar <[email protected]>


[1] https://lore.kernel.org/netdev/[email protected]/