Re: [PATCH net v2] vsock/bpf: release sock lock while waiting for data in recvmsg

[sashiko-bot@kernel.org]

> From: Jerome Mohm <jrmmhm.kernel@eldare.de>
> 
> vsock_bpf_recvmsg() takes lock_sock(sk) and holds it across the receive
> loop, including vsock_msg_wait_data(), which slept in wait_woken() without
> dropping the lock. When data arrived the transport's delivery context (the
> vsock-loopback worker, or the virtio/vhost rx path) called
> virtio_transport_recv_pkt() -> lock_sock() on the same socket and blocked,
> so neither side made progress and a blocking recv() hung; the hung-task
> watchdog reported the delivery worker in D state.
> 
> Dropping the socket lock around the wait is necessary but not sufficient:
> vsock_msg_wait_data() also did not loop and checked too few conditions,
> which left three further problems in the same helper.
> 
>  - It did not loop. Once the lock is dropped, a wakeup that is not for new
> [ ... ]
> 
> Fixes: 634f1a7110b4 ("vsock: support sockmap")
> Cc: stable@vger.kernel.org
> Assisted-by: LLM
> Signed-off-by: Jerome Mohm <jrmmhm.kernel@eldare.de>

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

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Sashiko AI review · https://sashiko.dev/#/patchset/20261001-kbh3-1-022-fix-v2-v1-1-cfae958a1976@eldare.de?part=1