[OpenAFS-devel] Android studio hangs openafs

[markus.suvanto@gmail.com]

ma, 2021-08-30 kello 18:10 +0000, Mark Vitale kirjoitti:
> Markus,
> 
> > On Aug 30, 2021, at 1:18 PM, markus.suvanto@gmail.com wrote:
> > 
> > ma, 2021-08-30 kello 02:14 +0000, Mark Vitale kirjoitti:
> > > 
> > > Lastly, if none of these shed light on the issue, please
> > > obtain a kernel backtrace while the problem is occurring:
> > > 
> > > # echo t > /proc/sysrq-trigger
> > > 
> > kernel config, openafs config.log and journalctl (sysrq-trigger stuff) are here:
> > https://drive.google.com/drive/folders/1ZiQInTxJlxLLebij2f9jMgBT6LaiUUnB?usp=sharing
> > 
> Thank you!  From the journalctl, here's the relevant task backtrace, edited for clarity:
> 
> elo 30 19:46:22 t470.station.com kernel: task:ApplicationImpl state:S stack:    0 pid: 2286 ppid:  1785 flags:0x00004000
> 
> elo 30 19:46:22 t470.station.com kernel: Call Trace:
> elo 30 19:46:22 t470.station.com kernel:  __schedule+0x254/0x12d0
> elo 30 19:46:22 t470.station.com kernel:  schedule+0x3f/0xa0
> elo 30 19:46:22 t470.station.com kernel:  afs_osi_SleepSig+0xfe/0x1e0 [libafs]
> elo 30 19:46:22 t470.station.com kernel:  afs_osi_Sleep+0x46/0x70 [libafs]
> elo 30 19:46:22 t470.station.com kernel:  afs_LookupAFSDB+0x150/0x2a0 [libafs]
> elo 30 19:46:22 t470.station.com kernel:  afs_lookup+0x13fc/0x1b60 [libafs]
> elo 30 19:46:22 t470.station.com kernel:  afs_linux_lookup+0x79/0x330 [libafs]
> elo 30 19:46:22 t470.station.com kernel:  __lookup_slow+0x7f/0x150
> elo 30 19:46:22 t470.station.com kernel:  walk_component+0x14f/0x1d0
> elo 30 19:46:22 t470.station.com kernel:  path_lookupat+0x69/0x1b0
> elo 30 19:46:22 t470.station.com kernel:  filename_lookup+0xc6/0x1d0
> elo 30 19:46:22 t470.station.com kernel:  vfs_statx+0x6d/0x110
> 
> This shows the AFS client waiting for completion of DNS cell name lookup (AFSDB/SRV records).
> The best way forward is to do a packet trace of the DNS traffic, then duplicate the
> problem to see what cell name we are trying to look up.  Most likely it will either
> be a real cell with a typo in the name, or it will be a metadata file that is not a cell name
> at all.


I'm using systemd-resolved.service
https://www.freedesktop.org/software/systemd/man/systemd-resolved.html#
https://www.freedesktop.org/software/systemd/man/nss-resolve.html
and I have symlinked 
/etc/resolv.conf -> /run/systemd/resolve/stub-resolv.conf
This configuration hangs android studio if project files are under /afs/...


But but... Then I removed this symbolick link
rm  /etc/resolv.conf  
and android studio start to work.
Somehow the problem is this compatibility link:

"systemd-resolved maintains the /run/systemd/resolve/stub-resolv.conf
file for compatibility with traditional Linux programs."

Let's see how the rest of my systemd works without /etc/resolv.conf compatibility link

-Markus