Re: Git clone failures on armv7, was Re: Git core dump checking out main on armv7

Reply: Mark Millard : "Re: Git clone failures on armv7, was Re: Git core dump checking out main on armv7"
In reply to: Mark Millard : "Re: Git clone failures on armv7, was Re: Git core dump checking out main on armv7"
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From: bob prohaska <fbsd_at_www.zefox.net>
Date: Thu, 27 Jun 2024 00:42:43 UTC
On Tue, Jun 25, 2024 at 05:51:59PM -0700, Mark Millard wrote:
> On Jun 25, 2024, at 17:28, bob prohaska <fbsd@www.zefox.net> wrote:
> 
> > On Sun, Jun 23, 2024 at 10:17:53AM -0700, Mark Millard wrote:
> >> On Jun 23, 2024, at 07:28, bob prohaska <fbsd@www.zefox.net> wrote:
> >>>> 
> >>>> It should be possible to mount the media normally used
> >>>> on one of the RPi2B v1.1's on, say, an RPi4B. One could
> >>>> then set up enough context to, say, chroot into the
> >>>> armv7 file system and try executing the clone in that
> >>>> context.
> >>>> 
> >>> 
> >>> That's physically not hard to do. Just power down the stable/14
> >>> Pi2 and plug the Pi2's boot disk into the Pi4.
> >> 
> >> Up to power issues, if bus powered.
> >> 
> >>>> The result would be using the RPi4B aarch64 kernel and
> >>>> the armv7 world. If that has no problems, then the armv7
> >>>> kernel likely has problems that contribute but the armv7
> >>>> world would be less likely to.
> >>>> 
> >>>> Doing this can get into first using the likes of
> >>>> (notation presumes use of /mnt at the mount point used
> >>>> above):
> >>>> 
> >>>> # mount -tdevfs devfs /mnt/dev/
> >>>> and possibly:
> >>>> # mount -tfdescfs none /mnt/fd/
> >> 
> >> That last should have been:
> >> 
> >> # mount -tfdescfs none /mnt/dev/fd/
> >> 
> >> Use of the likes of "mkdir -p . . ." may be required in
> >> order to have the directories for use as mount points
> >> if they are missing.
> >> 
> >>>> 
> >>>> before doing the likes of:
> >>>> 
> >>>> # chroot /mnt/
> >>>> # # EXPERIMENT HERE
> >>>> # exit
> >>>> 
> >>> I didn't realise that armv7 binaries would run under
> >>> an aarch64 kernel. Most convenient!
> >> 
> >> Such can be used to have a faster way to build armv7
> >> packages, that also allows larger armv7 processes to
> >> be involved (but still 32-bit limited with part of
> >> the address space reserved, for sure). Not only that,
> >> the process size limit is not a system
> >> size limit: An RPi4B with 8 GiBytes of RAM can have
> >> several armv7 processes at once that total over 4
> >> GiBytes of RAM in use at the time, no swapping
> >> needing to be involved.
> >> 
> >>>> Also, after exiting the chroot session, one would
> >>>> do the likes of:
> >>>> 
> >>>> # umount /mnt/dev/
> >>>> and possibly:
> >>>> # umount /mnt/fd/
> >> 
> >> That should have been (order dependent for fd inside dev):
> >> 
> >> possibly:
> >> # umount /mnt/dev/fd/
> >> 
> >> then:
> >> 
> >> # umount /mnt/dev/
> >> 
> >>>> 
> >>>> # umount /mnt/
> >>>> 
> >>> Thank you for the cleanup details!
> >> 
> > 
> > I ended up trying the experiment twice. The first try used the mistaken
> > mount -tfdescfs none /mnt/fd/ but since it was noted "possibly" I ignored
> > the error and the git clone command completed successfully. After noticing
> > your correction, the experiment was repeated and the clone failed:
> > 
> > root@nemesis:/usr/2ndgittest # git clone --depth=1 -o freebsd ssh://anongit@192.158.248.9/src.git .
> > Cloning into '.'...
> > remote: Enumerating objects: 104636, done.
> > remote: Counting objects: 100% (104636/104636), done.
> > remote: Compressing objects: 100% (88903/88903), done.
> > client_loop: send disconnect: Broken pipe88.34 MiB | 165.00 KiB/s
> 
> The above "client_loop: send disconnect: Broken pipe"
> seems to be the original error here.
> 
> It would be interesting to have evidence of how
> repeatable such is and what variety of other
> results happen.

Using chroot on the aarch64 -current Pi4 I made
repeated clones onto the mechanical hard disk
hosting the armv7 stable/14 filesystem. Couldn't
reproduce the error above in five tries.
Transcript at http://www.zefox.net/~fbsd/rpi2/git_problems/readme_aarch64


Then I moved the disk to an armv7 -current Pi2
using the same chroot setup, the clone with 
--depth=1 worked so I dropped the depth limit
and repeated; that caused a kernel panic.
A second try without chroot resulted in failure but no panic:
<jemalloc>: Should own extent_mutex_pool(17)47.25 MiB | 1.35 MiB/s  
error: index-pack died of signal 6

A repeat session produced an oft-seen failure:

root@www:/mnt # mkdir 3rdarmv7gittest
root@www:/mnt # cd 3rdarmv7gittest
root@www:/mnt/3rdarmv7gittest # git clone  -o freebsd ssh://anongit@192.158.248.9/src.git .
Cloning into '.'...
remote: Enumerating objects: 4511481, done.
remote: Counting objects: 100% (383480/383480), done.
remote: Compressing objects: 100% (28955/28955), done.
<jemalloc>: Should own extent_mutex_pool(17)47.25 MiB | 1.35 MiB/s  
error: index-pack died of signal 6
fatal: index-pack failed
root@www:/mnt/3rdarmv7gittest # ls
root@www:/mnt/3rdarmv7gittest # cd ..
root@www:/mnt # mkdir 4tharmv7gittest
root@www:/mnt # cd 4tharmv7gittest
root@www:/mnt/4tharmv7gittest # git clone -o freebsd ssh://anongit@192.158.248.9/src.git .
Cloning into '.'...
remote: Enumerating objects: 4511481, done.
remote: Counting objects: 100% (383480/383480), done.
remote: Compressing objects: 100% (28955/28955), done.
Receiving objects:  43% (1966916/4511481), 926.00 MiB | 626.00 KiB/s 
remote: Total 4511481 (delta 377747), reused 354525 (delta 354525), pack-reused 4128001 (from 1)
Receiving objects: 100% (4511481/4511481), 1.64 GiB | 705.00 KiB/s, done.
fatal: pack is corrupted (SHA1 mismatch)
fatal: index-pack failed
root@www:/mnt/4tharmv7gittest # 

No panic, however, and it seems reproducible:
root@www:/mnt # mkdir 5tharmv7gittest
root@www:/mnt # cd 5tharmv7gittest
root@www:/mnt/5tharmv7gittest # git clone -o freebsd ssh://anongit@192.158.248.9/src.git .
Cloning into '.'...
remote: Enumerating objects: 4511513, done.
remote: Counting objects: 100% (383480/383480), done.
remote: Compressing objects: 100% (28955/28955), done.
remote: Total 4511513 (delta 377756), reused 354525 (delta 354525), pack-reused 4128033 (from 1)
Receiving objects: 100% (4511513/4511513), 1.64 GiB | 1.28 MiB/s, done.
fatal: pack is corrupted (SHA1 mismatch)
fatal: index-pack failed
root@www:/mnt/5tharmv7gittest 
  
Not sure what to try next, thanks for reading this far! 

bob prohaska


Archived at 
http://www.zefox.net/~fbsd/rpi2/git_problems/readme_armv7