From: Jason Gunthorpe <jgg@ziepe.ca>
To: Leon Romanovsky <leon@kernel.org>
Cc: Chenguang Zhao <chenguang.zhao@linux.dev>,
andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com, linux-rdma@vger.kernel.org,
netdev@vger.kernel.org, tariqt@nvidia.com, mbloch@nvidia.com,
dtatulea@nvidia.com, shayd@nvidia.com, moshe@nvidia.com,
Chenguang Zhao <zhaochenguang@kylinos.cn>
Subject: Re: [PATCH rdma-next v3] RDMA/mlx5: quiesce CQ polling before device shutdown on reboot
Date: Fri, 7 Aug 2026 14:48:30 -0300 [thread overview]
Message-ID: <20260807174830.GF200537@ziepe.ca> (raw)
In-Reply-To: <20260716105008.GD357857@unreal>
On Thu, Jul 16, 2026 at 01:50:08PM +0300, Leon Romanovsky wrote:
> On Thu, Jul 16, 2026 at 05:03:37PM +0800, Chenguang Zhao wrote:
> > Hi, Leon
> > reboot -f skips orderly shutdown and goes directly to:
> >
> > kernel_restart_prepare() -> device_shutdown() -> mlx5 shutdown
> > Upper layers may still hold live CQs, while ib-comp-wq keeps
> > polling — a use-after-free race.
>
> The point is that this flow is neither RDMA- nor mlx5-specific, and it
> works as expected. mlx5 shutdown() stops the FW/HW, while the kernel
> stops and tears down the running threads.
I'm pretty sure we are missing stuff in the driver to synchronize
everything while it is doing a tear down or health recovery.
Ripping a driver out from under a still-running subsystem is hard,
this does seem like a real bug, but I also don't think the shutdown
handler is the right place to fix it..
What was the actual UAF scenario, we should take a look at that more
directly?
Jason
prev parent reply other threads:[~2026-08-07 17:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-15 8:23 [PATCH rdma-next v3] RDMA/mlx5: quiesce CQ polling before device shutdown on reboot Chenguang Zhao
2026-07-16 8:42 ` Leon Romanovsky
2026-07-16 9:03 ` Chenguang Zhao
2026-07-16 10:50 ` Leon Romanovsky
2026-08-07 17:48 ` Jason Gunthorpe [this message]
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