From: Jason Gunthorpe <jgg@ziepe.ca>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: OFED mailing list <linux-rdma@vger.kernel.org>,
Leon Romanovsky <leon@kernel.org>
Subject: Re: [rdma] "rdma link del" operation hangs at wait_for_completion() when a file descriptor is in use.
Date: Sat, 28 Feb 2026 12:43:36 -0400 [thread overview]
Message-ID: <20260228164336.GQ44359@ziepe.ca> (raw)
In-Reply-To: <d800131b-d257-4dc7-adcf-7c35e7a223d2@I-love.SAKURA.ne.jp>
On Sat, Feb 28, 2026 at 03:07:29PM +0900, Tetsuo Handa wrote:
> On 2025/12/04 17:26, Tetsuo Handa wrote:
> > I found that running the attached example program causes khungtaskd message. What is wrong?
>
> I found that this is a deadlock caused by "struct ib_device_ops"->disassociate_ucontext == NULL.
> If the thread which called ib_uverbs_remove_one() is unable to call ib_uverbs_release_file()
> from ib_uverbs_close() because it is blocked at
> wait_for_completion(), it forms a deadlock.
That doesn't sound right at all, the wait_for_completion is waiting
for other threads to let go of the context before closing it. rxe/etc
that syzkaller is testing don't support disassociate so they need to
wait.
If the wait gets stuck that is a different issue.
Jason
next prev parent reply other threads:[~2026-02-28 16:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-04 8:26 [rdma] "rdma link del" operation hangs at wait_for_completion() when a file descriptor is in use Tetsuo Handa
2026-02-28 6:07 ` Tetsuo Handa
2026-02-28 16:43 ` Jason Gunthorpe [this message]
2026-02-28 22:35 ` Tetsuo Handa
2026-03-01 7:43 ` Tetsuo Handa
2026-03-01 17:47 ` Jason Gunthorpe
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