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Date:   Wed, 16 Mar 2022 17:38:18 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Lee Jones <lee.jones@linaro.org>
Cc:     Pavel Begunkov <asml.silence@gmail.com>, stable@vger.kernel.org,
        Jens Axboe <axboe@kernel.dk>, io-uring@vger.kernel.org
Subject: Re: [PATCH] io_uring: return back safer resurrect
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On Wed, Mar 16, 2022 at 04:18:16PM +0000, Lee Jones wrote:
> Stable Team,
> 
> > Revert of revert of "io_uring: wait potential ->release() on resurrect",
> > which adds a helper for resurrect not racing completion reinit, as was
> > removed because of a strange bug with no clear root or link to the
> > patch.
> > 
> > Was improved, instead of rcu_synchronize(), just wait_for_completion()
> > because we're at 0 refs and it will happen very shortly. Specifically
> > use non-interruptible version to ignore all pending signals that may
> > have ended prior interruptible wait.
> > 
> > This reverts commit cb5e1b81304e089ee3ca948db4d29f71902eb575.
> > 
> > Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> > ---
> >  fs/io_uring.c | 18 ++++++++++++++----
> >  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> Please back-port this as far as it will apply.
> 
> Definitely through v5.10.y.
> 
> It solves a critical bug.
> 
> Subject: "io_uring: return back safer resurrect"
> 
> Upstream commit:: f70865db5ff35f5ed0c7e9ef63e7cca3d4947f04

It only applies to 5.10.y.  It showed up in 5.12, so if you want it
further back than 5.10.y, can you provide a working backport?

thanks,

greg k-h