Re: linux-next: Tree for Aug 1

[Ming Lei]

On Thu, Aug 2, 2018 at 7:47 AM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> On Wed, Aug 01, 2018 at 03:52:45PM -0700, James Bottomley wrote:
>> On Wed, 2018-08-01 at 15:48 -0700, Guenter Roeck wrote:
>> > On Wed, Aug 01, 2018 at 05:58:52PM +1000, Stephen Rothwell wrote:
>> > > Hi all,
>> > >
>> > > Changes since 20180731:
>> > >
>> > > The pci tree gained a conflict against the pci-current tree.
>> > >
>> > > The net-next tree gained a conflict against the bpf tree.
>> > >
>> > > The block tree lost its build failure.
>> > >
>> > > The staging tree still had its build failure due to an interaction
>> > > with
>> > > the vfs tree for which I disabled CONFIG_EROFS_FS.
>> > >
>> > > The kspp tree lost its build failure.
>> > >
>> > > Non-merge commits (relative to Linus' tree): 10070
>> > >  9137 files changed, 417605 insertions(+), 179996 deletions(-)
>> > >
>> > > -----------------------------------------------------------------
>> > > -----------
>> > >
>> >
>> > The widespread kernel hang issues are still seen. I managed
>> > to bisect it after working around the transient build failures.
>> > Bisect log is attached below. Unfortunately, it doesn't help much.
>> > The culprit is reported as:
>> >
>> > 2d542828c5e9 Merge remote-tracking branch 'scsi/for-next'
>> >
>> > The preceding merge,
>> >
>> > 453f1d821165 Merge remote-tracking branch 'cgroup/for-next'
>> >
>> > checks out fine, as does the tip of scsi-next (commit 103c7b7e0184,
>> > "Merge branch 'misc' into for-next"). No idea how to proceed.
>>
>> This sounds like you may have a problem with this patch:
>>
>>     commit d5038a13eca72fb216c07eb717169092e92284f1
>>      Author: Johannes Thumshirn <jthumshirn@xxxxxxx>
>>      Date:   Wed Jul 4 10:53:56 2018 +0200
>>
>>          scsi: core: switch to scsi-mq by default
>>
>> To verify, boot with the additional kernel parameter
>>
>> scsi_mod.use_blk_mq=0
>>
>> Which will reverse the effect of the above patch.
>>
> Yes, that fixes the problem.

That may not the root cause, given this issue is only started to
see from next-20180731, but d5038a13eca7 (scsi: core: switch to
scsi-mq by default)
has been in -next for quite a while.

Seems something new causes this issue.

Thanks,
Ming Lei