Re: [PATCH net v2] rds: ib: use rds_conn_drop() on protocol version mismatch

[sashiko-bot@kernel.org]

> From: Aohan Mei <henrymei@tencent.com>
> 
> rds_ib_cm_connect_complete() runs from the RDMA-CM event handler with
> conn->c_cm_lock held.  When the peer negotiates a protocol version
> older than RDS_PROTOCOL_COMPAT_VERSION, the handler calls
> rds_conn_destroy(), which is only safe in the rmmod path: it
> synchronously tears the connection down and flush_work()es the
> shutdown work cp_down_w.
> 
> That shutdown work (rds_conn_shutdown()) needs cp_cm_lock, which is
> the very lock the event handler still holds, so the flush never
> completes: the two workers wait on each other and the RDS connection
> workqueues stall for good.
> 
> All other RDMA-CM failure paths (REJECTED, CONNECT_ERROR,
> DISCONNECTED) use rds_conn_drop(), which marks the connection
> RDS_CONN_ERROR and schedules the shutdown work asynchronously.  Use
> it here as well.
> 
> Fixes: f147dd9ecabf ("RDS/IB: Disallow connections less than RDS 3.1")
> Reported-by: TencentOS Corvus AI <corvus@tencent.com>
> Cc: stable@vger.kernel.org
> Assisted-by: CodeBuddy:Kimi-K3
> Reviewed-by: Allison Henderson <achender@kernel.org>
> Signed-off-by: Aohan Mei <henrymei@tencent.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260911073436.3542080-1-ljp1205831794@gmail.com?part=1