Re: building netbsd-9 2 'sync' processes stuck in 'tstile'

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Fri, 7 May 2021 17:39:47 -0500 (CDT)
    From:        "John D. Baker" <jdbaker%consolidated.net@localhost>
    Message-ID:  <Pine.NEB.4.64.2105071728050.1246%spike.technoskunk.fur@localhost>

  | So far, the now 6 'sync' processes have been stuck in "tstile" for 4
  | days.

They are extermely unlikely to ever go away, that's a kernel locking bug.
What version is the system you're running (not the one you're building,
that's irrelevant to this) ?

You need a reboot to fix this.

  | Other than being unable to build/link any kernels, the system is
  | fine and its primary functions as file server (NFS, SaMBa, AppleTalk),
  | backup DNS and NTP server are unaffected as are its clients (i.e., every
  | other machine on my LAN).  CVS updates to the various trees complete
  | without problems.

Some little used vnode is likely locked.   As long as nothing references that
particular one, everything is fine.   Anything which accesses the file (in
the generic sense, ie: including directories etc) in question will hang.

  | Once other clients are either finished with their tasks or at least reach
  | a convenient stopping point, the machine will be rebooted so I can test
  | a possible solution to kern/55115.

That will clear the lock...   Whether it happens again or not all depends
on what was locked (not so easy to discover usually) and what caused it to
happen.

kre