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From:   zhenguo yao <yaozhenguo1@gmail.com>
Date:   Mon, 12 Jul 2021 17:08:48 +0800
Message-ID: <CA+WzARky9K+pATZb5mvOpekYa0jFsE6GQ7pR9XbZ5xoEPTgw7w@mail.gmail.com>
Subject: Re: [PATCH] task_work: return -EBUSY when adding same work
To:     Jens Axboe <axboe@kernel.dk>
Cc:     oleg@redhat.com, linux-kernel@vger.kernel.org, yaozhenguo@jd.com
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OK=EF=BC=8CGot it.  My patch does not cover this situation.  It seems that
there is always dead-loop when same works are added to the list.

Jens Axboe <axboe@kernel.dk> =E4=BA=8E2021=E5=B9=B47=E6=9C=8812=E6=97=A5=E5=
=91=A8=E4=B8=80 =E4=B8=8A=E5=8D=8810:44=E5=86=99=E9=81=93=EF=BC=9A
>
> On 7/11/21 8:13 PM, zhenguo yao wrote:
> > Yes I hit this condition.  The caller is queue_task_work in
> > arch/x86/kernel/cpu/mce/core.c.
> > It is really a BUG. I have submitted another patch to fix it:
> > https://lkml.org/lkml/2021/7/9/186.
>
> That patch seems broken, what happens if mce_kill_me is added already,
> but it isn't the first work item in the list?
>
> --
> Jens Axboe
>