Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 22 Oct 2018 18:43:21 -0700
From:      Mark Millard <marklmi@yahoo.com>
To:        Warner Losh <imp@bsdimp.com>, Konstantin Belousov <kib@freebsd.org>
Cc:        Toomas Soome <tsoome@me.com>, FreeBSD Current <freebsd-current@freebsd.org>, FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org>
Subject:   Re: head -r338804 boots threadripper 1950X fine; head -r338810+ do not; -r338807 seems implicated
Message-ID:  <302639EA-55AA-4A41-BC03-4D48E6A09000@yahoo.com>
In-Reply-To: <16BF1504-AD3B-4B5F-A728-43C2A777A082@yahoo.com>
References:  <79973E2B-F5C4-4E7C-B92B-1C8D4441C7D1@yahoo.com> <ACBB38EF-9A6A-40E5-AB6C-EEB9E292A919@yahoo.com> <EDBFFACB-8582-4B16-AC1A-63F8C86C9BA4@yahoo.com> <CANCZdfo=uqLn16r0FShz=WEv3Z34LbmC1gqzKabwfr3gEUXsJg@mail.gmail.com> <CANCZdfoHg8=FfuJchyPJ9qBDZBkR_7nYTWPiQedZkW4Cs1pR5A@mail.gmail.com> <3CA4C94F-A062-44FE-B507-948A6F88C83D@me.com> <085BCA2B-4451-406C-9CEE-57D8B8008201@yahoo.com> <9AEF5EB3-C393-44D1-9BD4-D0E59FE97CCE@me.com> <08B26F92-F1F5-4F51-8DC4-EDDC6DD493B2@yahoo.com> <CANCZdfoeb6G4VxAnYmy0=1EKNszihccO16izpF7X%2Br7GAQO7yQ@mail.gmail.com> <16BF1504-AD3B-4B5F-A728-43C2A777A082@yahoo.com>

next in thread | previous in thread | raw e-mail | index | archive | help
[I' unable to reproduce the under-Hyper-V early kernel
crash for WITH_ZFS=3D (implicit) build that includes the
for-loaders patch I was given to try.]

On 2018-Oct-22, at 10:01 AM, Mark Millard <marklm at yahoo.com> wrote:

> [I will note the the loader problem has been shown to
> not be involved in the kernel problem that this
> "Subject:" was originally for.]
>=20
> On 2018-Oct-22, at 9:26 AM, Warner Losh <imp at sdimp.com> wrote:
>=20
>> On Mon, Oct 22, 2018 at 6:39 AM Mark Millard <marklmi@yahoo.com> =
wrote:
>>> On 2018-Oct-22, at 4:07 AM, Toomas Soome <tsoome at me.com> wrote:
>>>=20
>>>> On 22 Oct 2018, at 13:58, Mark Millard <marklmi at yahoo.com> =
wrote:
>>>>>=20
>>>>> On 2018-Oct-22, at 2:27 AM, Toomas Soome <tsoome at me.com> wrote:
>>>>>>=20
>>>>>>> On 22 Oct 2018, at 06:30, Warner Losh <imp@bsdimp.com> wrote:
>>>>>>>=20
>>>>>>> On Sun, Oct 21, 2018 at 9:28 PM Warner Losh <imp@bsdimp.com> =
wrote:
>>>>>>>=20
>>>>>>>>=20
>>>>>>>>=20
>>>>>>>> On Sun, Oct 21, 2018 at 8:57 PM Mark Millard via freebsd-stable =
<
>>>>>>>> freebsd-stable@freebsd.org> wrote:
>>>>>>>>=20
>>>>>>>>> [I built based on WITHOUT_ZFS=3D for other reasons. But,
>>>>>>>>> after installing the build, Hyper-V based boots are
>>>>>>>>> working.]
>>>>>>>>>=20
>>>>>>>>> On 2018-Oct-20, at 2:09 AM, Mark Millard <marklmi at =
yahoo.com> wrote:
>>>>>>>>>=20
>>>>>>>>>> On 2018-Oct-20, at 1:39 AM, Mark Millard <marklmi at =
yahoo.com> wrote:
>>>>>>>>>> . . .
>>>>>>>=20
>>>>>>=20
>>>>>> It would help to get output from loader lsdev -v command.
>>>>>=20
>>>>> That turned out to be very interesting: The non-ZFS loader
>>>>> crashes during the listing, during disk8, which shows a
>>>>> x0 instead of a x512.
>>>>>=20
>>>>=20
>>>> Yes, thats the root cause there. The non-zfs loader does only =
*read* the boot disk, thats why the issue was not revealed there.=20
>>>>=20
>>>> It would help to identify the sector size for that disk, at least =
from OS, so we can compare with what we can get from INT13.
>>>>=20
>>>> I have pretty good idea what to look there, but I am afraid we need =
to run few tests with you to understand why that disk is reporting =
sector size 0 there.
>>>>=20
>>>>=20
>>>=20
>>> Looks like I guessed wrong about the device
>>> for "drive8".
>>>=20
>>> So I unplugged the only other external
>>> storage device, so the original drives
>>> 0-13 become 0-11 overall.
>>>=20
>>> The machine has a multi-LUN media card reader with
>>> no cards plugged in. It is built-in rather than
>>> one that I plugged into a port. It has 4 LUN's.
>>>=20
>>> So 8+4=3D12 and drives 0-7 show up with media before
>>> it tries any of the 4 LUN's with no card in place.
>>>=20
>>> I conclude that "drive8" is an empty LUN in a media
>>> card reader.
>>>=20
>>> I conclude that there is no sector size available for
>>> any of the empty LUNs in the media reader.
>>>=20
>> I think you are probably right and we're hitting some divide by 0 =
error when we should just ignore the disk.
>=20
> In the Hyper-V context, the loader and kernel do not
> see the 4-LUN media reader at all: only drives with
> normal freebsd-* style partitions and free space.
> This explains why I did not see a loader problem
> in that context.
>=20
> So I conclude that the kernel crash under Hyper-V
> associated with -r338807 is a separate issue even
> though WITHOUT_ZFS=3D seems to have avoided the
> crash.
>=20
> My plan is to continue with the -r338807 investigation
> after the loader problem is fixed in my builds. Then
> I've go back to trying builds using WITH_ZFS=3D (implicit),
> both native boots and Hyper-V based ones.

So much for my ability to make that inference correctly:

The WITH_ZFS=3D (implicit) build worked fine for booting
natively and via Hyper-V when the patch to fix the loaders
was included in what to build. I'm now unable to reproduce
this kernel-time crash.

The patch was from: https://reviews.freebsd.org/D11174

The empty LUN's in the media reader now get messages that
look something like:

disk8: Read 1 sector(s) from 0 to 0xffffe000 (0x8000): 0x31

early in the loader activity.

=3D=3D=3D
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?302639EA-55AA-4A41-BC03-4D48E6A09000>