On Wed, Jul 31, 2019 at 05:46:08PM +0200, Raimo Niskanen wrote: > I have enabled Witness, it went so-so. We'll see what it catches. > > I downloaded 6.5 amd64 src.tar.gz and sys.tar.gz, unpacked them, > applied all patches for stable 001-006 and built a kernel with: > include "arch/amd64/conf/GENERIC" > option MULTIPROCESSOR > option MP_LOCKDEBUG > option WITNESS > > Then I activated in /etc/sysctl.conf: > ddb.console=1 > kern.witness.locktrace=1 > kern.witness.watch=3 > > For fun, I pressed Ctrl+Alt+Esc at the console, got a ddb> prompt and typed > "show witness". It printed lots of info, I scrolled down to the end, but > during the printout there was an UVM fault: > > Spin locks: > /usr/src/sys/.... > : > bla bla bla > : > uvm_fault(0xffffffff81e03b50, 0xffff800022368360, 0, 1) -> e > kernel: page fault trap, code=0 > Faulted in DDB: continuing...
The output of "show witness" is unlikely to be useful in your case. It is more of a tool for debugging witness. You can ignore it. However, "show all locks" might display interesting information after a witness-related panic.
