Are you sure the real problem is not the one fixed by this commit?
commit f1c635b439a5c01776fe3a25b1e2dc546ea82e6f
Author: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx>
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 <sthemmin@xxxxxxxxxxxxx>
Reviewed-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
-----Original Message-----
From: Joseph Salisbury [mailto:joseph.salisbury@xxxxxxxxxxxxx]
Sent: Monday, March 27, 2017 1:22 PM
To: Long Li <longli@xxxxxxxxxxxxx>
Cc: KY Srinivasan <kys@xxxxxxxxxxxxx>; Martin K. Petersen <martin.petersen@xxxxxxxxxx>; Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>; jejb@xxxxxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx; linux-scsi <linux-scsi@xxxxxxxxxxxxxxx>; LKML <linux-kernel@xxxxxxxxxxxxxxx>; stable@xxxxxxxxxxxxxxx; Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
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 <longli@xxxxxxxxxxxxx>
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
