Re: df stuck in tstile

[Martin Husemann <martin%duskware.de@localhost>]

On Wed, Jan 30, 2019 at 04:14:49PM +0000, Steve Blinkhorn wrote:
> I think I'm probably out of my depth on this one.  I used to get this
> kind of problem on the machines these replace, and became convinced
> that that was a bad block issue (which got aired on one lof the other
> lists - they were x86 macnines).  Once there was one process stuck in
> tstile, the problem began to accumulate, and the only solution was a
> periodic reboot.  IIRC the problem started with a df.

This usually means that some driver is still trying to write a file system
buffer back to disk (or NFS server or whatever), or there is a bug in a
drivers error path and e.g. you hit some error condition and the driver
did not handle that correctly, so now some vnode or file system lock is
still blocked and everything that waits for it to become free gets blocked
in tstile.

The backtraces of various blocking kernel threads would give us a hint
which driver to look at. Can you drop into the debugger and force a
crash dump + reboot? Then we could start looking at the kernel crash
and extract better info from it.

Martin