Re: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM)

From	Will Deacon <will.deacon@arm.com>
Newsgroups	linux.kernel
Subject	Re: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM)
Date	2016-02-12 17:00 +0100
Message-ID	<r1oiu-ws-23@gated-at.bofh.it> (permalink)
References	<r14a7-44q-17@gated-at.bofh.it> <r14MN-4Cs-9@gated-at.bofh.it> <r15zb-4W1-9@gated-at.bofh.it> <r1iPM-5vL-19@gated-at.bofh.it> <r1iZr-5zo-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Fri, Feb 12, 2016 at 11:12:34AM +0100, Sebastian Ott wrote:
> On Fri, 12 Feb 2016, Will Deacon wrote:
> > On Thu, Feb 11, 2016 at 08:57:02PM +0100, Gerald Schaefer wrote:
> > > On Thu, 11 Feb 2016 21:09:42 +0200
> > > "Kirill A. Shutemov" <kirill@shutemov.name> wrote:
> > > > On Thu, Feb 11, 2016 at 07:22:23PM +0100, Gerald Schaefer wrote:
> > > > > Sebastian Ott reported random kernel crashes beginning with v4.5-rc1 and
> > > > > he also bisected this to commit 61f5d698 "mm: re-enable THP". Further
> > > > > review of the THP rework patches, which cannot be bisected, revealed
> > > > > commit fecffad "s390, thp: remove infrastructure for handling splitting PMDs"
> > > > > (and also similar commits for other archs).

[...]

> > Do you have a reliable way to trigger the "random kernel crashes"? We've not
> > seen anything reported on arm64, but I don't see why we wouldn't be affected
> > by the same bug and it would be good to confirm and validate a fix.
> 
> My testcase was compiling the kernel. Most of the time my test system
> didn't survive a single compile run. During bisect I did at least 20
> compile runs to flag a commit as good.

I've been building kernels all day with -rc3 on my arm64 box and haven't
seen any problems yet.. :/.

I'll leave it going over the weekend.

Will

Thread

[BUG] random kernel crashes after THP rework on s390 (maybe also on  PowerPC and ARM) Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-02-11 19:30 +0100
  Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-02-11 20:10 +0100
    Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-02-11 20:20 +0100
      Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) Sebastian Ott <sebott@linux.vnet.ibm.com> - 2016-02-12 13:30 +0100
    Re: [BUG] random kernel crashes after THP rework on s390 (maybe  also on PowerPC and ARM) Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-02-11 21:00 +0100
      Re: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM) "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2016-02-12 05:10 +0100
        Re: [BUG] random kernel crashes after THP rework on s390 (maybe  also on PowerPC and ARM) Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-02-12 13:10 +0100
          Re: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM) "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2016-02-12 17:20 +0100
      Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) Will Deacon <will.deacon@arm.com> - 2016-02-12 11:10 +0100
        Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) Sebastian Ott <sebott@linux.vnet.ibm.com> - 2016-02-12 11:20 +0100
          Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) Will Deacon <will.deacon@arm.com> - 2016-02-12 17:00 +0100
      Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-02-12 16:50 +0100
        Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) Christian Borntraeger <borntraeger@de.ibm.com> - 2016-02-12 17:00 +0100
          Re: [BUG] random kernel crashes after THP rework on s390 (maybe  also on PowerPC and ARM) Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-02-12 18:20 +0100
            Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-02-13 00:20 +0100
              Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) Sebastian Ott <sebott@linux.vnet.ibm.com> - 2016-02-13 13:00 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-02-15 16:50 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) Sebastian Ott <sebott@linux.vnet.ibm.com> - 2016-02-15 17:40 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe  also on PowerPC and ARM) Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-02-15 19:40 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-02-16 00:30 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) Sebastian Ott <sebott@linux.vnet.ibm.com> - 2016-02-16 11:00 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe  also on PowerPC and ARM) Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-02-16 17:30 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-02-17 16:30 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) Christian Borntraeger <borntraeger@de.ibm.com> - 2016-02-16 19:50 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe  also on PowerPC and ARM) Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-02-17 20:20 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-02-18 08:00 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe  also on PowerPC and ARM) Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-02-18 16:10 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-02-18 18:10 +0100
                Re: [BUG] random kernel crashes after THP rework on s390 (maybe also  on PowerPC and ARM) Sebastian Ott <sebott@linux.vnet.ibm.com> - 2016-02-19 15:20 +0100
              Re: [BUG] random kernel crashes after THP rework on s390 (maybe  also on PowerPC and ARM) Gerald Schaefer <gerald.schaefer@de.ibm.com> - 2016-02-15 17:50 +0100

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