On Wed, Jul 09, 2025 at 11:31:07AM -0300, K R wrote: > On Wed, Jul 9, 2025 at 10:34 AM Claudio Jeker <[email protected]> > wrote: > > > > On Wed, Jul 09, 2025 at 10:06:59AM -0300, K R wrote: > > > Please find below another debug session. > > > > > > The machine is amd64, 32 cpus, 128GB RAM. Can reproduce the hang every > > > time now by doing: > > > > > > cd /usr/ports/lang/rust > > > while : > > > do > > > make clean=build > > > make > > > done > > > > > > Tested with a -current kernel, compiled with WITNESS and MP_LOCKDEBUG > > > and __mp_lock_spinout = 50L * INT_MAX. > > > > > > I've included traces on all the cpus with state "stopped". Couldn't > > > get the "stopping" cpus to stop with mach stopcpu N. Trying to mach > > > ddbcpu N on a "stopping" cpu will freeze ddb. > > > > You are not running the latest version of -current. This issue has been > > fixed a few days ago. > > You are right, I've just got the latest version, recompiled and > rebooted. Thanks for the warning. > > > > > Could you also include a dmesg of that box. > > Attached below. So you have a dual socket Intel box. So this may be indeed a similar issue where the current mutex implementation is to unfair and starves cores until they hit the MP_LOCKDEBUG trigger.
-- :wq Claudio
