I think we need both going forward. They addressed different problems.

> -----Original Message-----
> From: devel [mailto:driverdev-devel-boun...@linuxdriverproject.org] On
> Behalf Of Cathy Avery
> Sent: Thursday, March 30, 2017 6:52 AM
> To: driverdev-devel@linuxdriverproject.org; Stephen Hemminger
> <sthem...@microsoft.com>; gre...@linuxfoundation.org
> Subject: Re: [REGRESSION][Stable][v3.12.y][v4.4.y][v4.9.y][v4.10.y][v4.11-rc1]
> scsi: storvsc: properly set residual data length on errors
> 
> Hi,
> 
> So which commit is moving forward and which one is not?
> 
> f1c635b439a5c01776fe3a25b1e2dc546ea82e6f or
> 40630f462824ee24bc00d692865c86c3828094e0?
> 
> We have backported 40630f462824ee24bc00d692865c86c3828094e0 and I am
> unclear if this is a regression and must be removed or it is a regression but 
> is
> fixed by f1c635b439a5c01776fe3a25b1e2dc546ea82e6f and can remain.
> 
> Thanks,
> 
> Cathy
> 
> On 03/28/2017 12:14 PM, Stephen Hemminger wrote:
> > I decided not to send it to stable since problem was only observed on
> > 4.11 but it is probably endemic to all GEN2 VM's
> >
> > -----Original Message-----
> > From: Joseph Salisbury [mailto:joseph.salisb...@canonical.com]
> > Sent: Tuesday, March 28, 2017 7:29 AM
> > To: Stephen Hemminger <sthem...@microsoft.com>; Long Li
> > <lon...@microsoft.com>
> > Cc: KY Srinivasan <k...@microsoft.com>; Martin K. Petersen
> > <martin.peter...@oracle.com>; Haiyang Zhang
> <haiya...@microsoft.com>;
> > j...@linux.vnet.ibm.com; de...@linuxdriverproject.org; linux-scsi
> > <linux-s...@vger.kernel.org>; LKML <linux-ker...@vger.kernel.org>;
> > sta...@vger.kernel.org; Greg KH <gre...@linuxfoundation.org>
> > Subject: Re:
> > [REGRESSION][Stable][v3.12.y][v4.4.y][v4.9.y][v4.10.y][v4.11-rc1]
> > scsi: storvsc: properly set residual data length on errors
> >
> > On 03/27/2017 06:14 PM, Stephen Hemminger wrote:
> >> Are you sure the real problem is not the one fixed by this commit?
> >>
> >> commit f1c635b439a5c01776fe3a25b1e2dc546ea82e6f
> >> Author: Stephen Hemminger <step...@networkplumber.org>
> >> Date:   Tue Mar 7 09:15:53 2017 -0800
> >>
> >>      scsi: storvsc: Workaround for virtual DVD SCSI version
> >>
> >>      Hyper-V host emulation of SCSI for virtual DVD device reports SCSI
> >>      version 0 (UNKNOWN) but is still capable of supporting REPORTLUN.
> >>
> >>      Without this patch, a GEN2 Linux guest on Hyper-V will not boot 4.11
> >>      successfully with virtual DVD ROM device. What happens is that the
> SCSI
> >>      scan process falls back to doing sequential probing by INQUIRY.  But 
> >> the
> >>      storvsc driver has a previous workaround that masks/blocks all errors
> >>      reports from INQUIRY (or MODE_SENSE) commands.  This workaround
> causes
> >>      the scan to then populate a full set of bogus LUN's on the target and
> >>      then sends kernel spinning off into a death spiral doing block reads 
> >> on
> >>      the non-existent LUNs.
> >>
> >>      By setting the correct blacklist flags, the target with the DVD device
> >>      is scanned with REPORTLUN and that works correctly.
> >>
> >>      Patch needs to go in current 4.11, it is safe but not necessary in 
> >> older
> >>      kernels.
> >>
> >>      Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
> >>      Reviewed-by: K. Y. Srinivasan <k...@microsoft.com>
> >>      Reviewed-by: Christoph Hellwig <h...@lst.de>
> >>      Signed-off-by: Martin K. Petersen <martin.peter...@oracle.com>
> >>
> >> -----Original Message-----
> >> From: Joseph Salisbury [mailto:joseph.salisb...@canonical.com]
> >> Sent: Monday, March 27, 2017 1:22 PM
> >> To: Long Li <lon...@microsoft.com>
> >> Cc: KY Srinivasan <k...@microsoft.com>; Martin K. Petersen
> >> <martin.peter...@oracle.com>; Haiyang Zhang
> <haiya...@microsoft.com>;
> >> Stephen Hemminger <sthem...@microsoft.com>;
> j...@linux.vnet.ibm.com;
> >> de...@linuxdriverproject.org; linux-scsi
> >> <linux-s...@vger.kernel.org>; LKML <linux-ker...@vger.kernel.org>;
> >> sta...@vger.kernel.org; Greg KH <gre...@linuxfoundation.org>
> >> Subject:
> >> [REGRESSION][Stable][v3.12.y][v4.4.y][v4.9.y][v4.10.y][v4.11-rc1]
> >> scsi: storvsc: properly set residual data length on errors
> >>
> >> Hi Long Li,
> >>
> >> A kernel bug report was opened against Ubuntu [0].  After a kernel
> >> bisect, it was found that reverting the following commit resolved this bug:
> >>
> >> commit 40630f462824ee24bc00d692865c86c3828094e0
> >> Author: Long Li <lon...@microsoft.com>
> >> Date:   Wed Dec 14 18:46:03 2016 -0800
> >>
> >>      scsi: storvsc: properly set residual data length on errors
> >>
> >>
> >> The regression was introduced in mainline as of v4.11-rc1.  It was
> >> also cc'd to stable and has landed in v3.12.y, v4.4.y, v4.9.y and v4.10.y.
> >>
> >>
> >> This regression seems pretty severe since it's preventing virtual
> >> machines from booting.  It's affecting a couple of users so far.  I
> >> was hoping to get your feedback, since you are the patch author.  Do
> >> you think gathering any additional data will help diagnose this
> >> issue, or would it be best to submit a revert request?
> >>
> >>
> >> Thanks,
> >>
> >> Joe
> >>
> >>
> >> [0] http://pad.lv/1674635
> >>
> >>
> > Hi Stephen,
> >
> >
> > Thanks again for pointing out commit
> > f1c635b439a5c01776fe3a25b1e2dc546ea82e6f.  It does indeed fix the bug.
> > I noticed the commit was not cc'd to stable.  Would it be possible to
> > do that?
> >
> >
> > Thanks,
> >
> >
> > Joe
> >
> >
> > _______________________________________________
> > devel mailing list
> > de...@linuxdriverproject.org
> > http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-dev
> > el
> >
> 
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