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Date:   Tue, 29 Nov 2022 16:34:02 -0800
From:   Samuel Mendoza-Jonas <samjonas@amazon.com>
To:     Greg KH <gregkh@linuxfoundation.org>
CC:     Shakeel Butt <shakeelb@google.com>,
        Michele Jr De Candia <mdecandia@gmail.com>,
        <akpm@linux-foundation.org>, <bsegall@google.com>,
        <edumazet@google.com>, <jbaron@akamai.com>, <khazhy@google.com>,
        <linux-kernel@vger.kernel.org>, <r@hev.cc>, <rpenyaev@suse.de>,
        <stable@kernel.org>, <stable@vger.kernel.org>,
        <torvalds@linux-foundation.org>, <viro@zeniv.linux.org.uk>,
        <benh@amazon.com>, <risbhat@amazon.com>
Subject: Re: [PATCH 5.4 051/389] epoll: autoremove wakers even more
 aggressively
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On Thu, Oct 27, 2022 at 12:09:30PM +0200, Greg KH wrote:
> On Wed, Oct 26, 2022 at 11:48:01AM -0700, Shakeel Butt wrote:
> > On Wed, Oct 26, 2022 at 11:44 AM Michele Jr De Candia
> > <mdecandia@gmail.com> wrote:
> > >
> > > Hi Greg,
> > > sorry for the confusion.
> > >
> > > I'm running a container-based app on top of Ubuntu Linux 20.04 and linux kernel 5.4 always updated with latest patches.
> > >
> > > Updating from 5.4.210 to 5.4.211 we faced the hang up issue and searching for the cause we have tested that
> > > hangup occurs only with this patch
> > >
> > > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.4.y&id=cf2db24ec4b8e9d399005ececd6f6336916ab6fc
> > >
> > > While understanding root cause, wt the moment we reverted it and hang up does not occurs (actually we are running 5.4.219 without that patch).
> > >
> > > Michele
> > >
> > 
> > Hi Michele, can you try the latest upstream kernel and see if the
> > issue repro ther? Also is it possible to provide a simplified repro of
> > the issue?
> 
> Also is this issue on 5.10.y and 5.15.y?
> 
> thanks,
> 
> greg k-h

Following up this email thread for those of us who were watching it; it
looks like this was only an issue on 5.4.y due to some missing
backports that this change depended on - see this thread for details:
https://lore.kernel.org/lkml/Y38h9oe4ZEGNd7Zx@quatroqueijos.cascardo.eti.br/T/

Cheers,
Sam