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From:   Katrin Jo <zys.zljxml@gmail.com>
Date:   Thu, 30 Jun 2022 16:12:03 +0800
Message-ID: <CAOaDN_Tb9DJhOPXc=r9anoY3pdK3TcjX7Mwg2WQR_GUH66raqQ@mail.gmail.com>
Subject: Re: [PATCH] kernfs: fix potential NULL dereference in __kernfs_remove
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     tj@kernel.org, viro@zeniv.linux.org.uk,
        LKML <linux-kernel@vger.kernel.org>,
        katrinzhou <katrinzhou@tencent.com>
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On Thu, Jun 30, 2022 at 3:28 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Thu, Jun 30, 2022 at 12:00:47PM +0800, zys.zljxml@gmail.com wrote:
> > From: katrinzhou <katrinzhou@tencent.com>
> >
> > When lockdep is enabled, lockdep_assert_held_write would
> > cause potential NULL pointer dereference.
> >
> > Fix the folloeing smatch warnings:
> >
> > fs/kernfs/dir.c:1353 __kernfs_remove() warn: variable dereferenced before check 'kn' (see line 1346)
> >
> > Signed-off-by: katrinzhou <katrinzhou@tencent.com>
>
> Can you please submit this with your legal name that you use to sign
> documents?
>
> Also, what commit id does this fix?  Did you actually hit this with a
> real workload?  How can this be reproduced and tested?
>
> thanks,
>
> greg k-h

Sorry for the formatting issue. I'll submit a new patch soon.
This problem is found via static code analysis, and by now
I have not reproduced / tested it.

Best regards,
Katrin