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Subject: Re: [PATCH 2/2] scsi: ufs: Protect PM ops and err_handler from user
 access through sysfs
From:   Bean Huo <huobean@gmail.com>
To:     Can Guo <cang@codeaurora.org>
Cc:     asutoshd@codeaurora.org, nguyenb@codeaurora.org,
        hongwus@codeaurora.org, ziqichen@codeaurora.org,
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        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Nitin Rawat <nitirawa@codeaurora.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Satya Tangirala <satyat@google.com>,
        open list <linux-kernel@vger.kernel.org>
Date:   Mon, 11 Jan 2021 11:04:31 +0100
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On Mon, 2021-01-11 at 17:22 +0800, Can Guo wrote:
> > > meaning you are tring to access a register when clocks are
> > > disabled.
> > > This
> > > leads to system CRASH.
> > > 
> > 
> > OK, let it simple, share this kind of crash log becuase of access
> > sysfs
> > node in the shutdown flow.
> > 
> > 
> > > [2] OCP is over current protection. While UFS shutting down, you
> > > may
> > > have put UFS regulators to LPM. After that, if you are still
> > > trying
> > > to
> > > talk to UFS, OCP can happen on VCCQ/VCCQ2. This leads to system
> > > CRASH
> > > too.
> > 
> > the same as above, share the crash log.
> > 
> 
> If you have hand-on experiences on NoC and/or OCP issues, you won't
> ask
> for the crash log. The tricky parts about critial NoC and OCP issues
> is

OK, interesting. would you tell me which register access node in ufs-
sysfs.c can trigger this crash? let me verify your statement.


Bean

>