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References: <20221231055310.2040648-1-yoochan1026@gmail.com> <Y7AHvYfZreO/G/kT@kroah.com>
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From:   Yoochan Lee <yoochan1026@gmail.com>
Date:   Sat, 31 Dec 2022 19:05:36 +0900
Message-ID: <CALQpDLfMjAE9_VtMO6e_iiPrciFNbksLQT3AB3QTGwZCNf5=sA@mail.gmail.com>
Subject: Re: [PATCH] misc: hpilo: Fix use-after-free in ilo_open
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     matt.hsiao@hpe.com, arnd@arndb.de, linux-kernel@vger.kernel.org
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Hi,

I haven't tested with a physical device cause I don't have a real device.
I found this bug through static analysis.

This type of bug is similar to [1] and [2].

And I'm sorry that my patch is incorrect.
It's my first time patching a Linux kernel myself.
So I'm not familiar with how to patch it well (For this reason, my
patches are referred to [1] and [2]).
Then, how should I patch it?

[1] https://lore.kernel.org/lkml/20220919040457.GA302681@ubuntu/
[2] https://lore.kernel.org/lkml/20220919101825.GA313940@ubuntu/

2022=EB=85=84 12=EC=9B=94 31=EC=9D=BC (=ED=86=A0) =EC=98=A4=ED=9B=84 6:58, =
Greg KH <gregkh@linuxfoundation.org>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> On Sat, Dec 31, 2022 at 02:53:10PM +0900, Yoochan Lee wrote:
> > --- a/drivers/misc/hpilo.h
> > +++ b/drivers/misc/hpilo.h
> > @@ -62,6 +62,7 @@ struct ilo_hwinfo {
> >       spinlock_t fifo_lock;
> >
> >       struct cdev cdev;
> > +     struct kref refcnt;
>
> This is obviously incorrect, please never have 2 reference counts for
> the same structure.
>
> greg k-h