Can confirm -- same general backtrace I sent in earlier. That means the bug is: 1.) Not architecture specific 2.) Not filesystem specific I was originally concerned it was related to BTRFS or POWER-specific, good to see it is not. ----- Original Message ----- > From: "hedrick" > To: "J. Bruce Fields" > Cc: "Timothy Pearson" , "Chuck Lever" , "linux-nfs" > > Sent: Monday, August 9, 2021 1:51:05 PM > Subject: Re: CPU stall, eventual host hang with BTRFS + NFS under heavy load > I have. I was trying to avoid a reboot. > > By the way, after the first failure, during reboot, syslog showed the following. > I’m unclear what it means, bu tit looks ike it might be from the failure > > > >> On Aug 9, 2021, at 2:49 PM, J. Bruce Fields wrote: >> >> On Mon, Aug 09, 2021 at 02:38:33PM -0400, hedrick@rutgers.edu wrote: >>> Does setting /proc/sys/fs/leases-enable to 0 work while the system is >>> up? I was expecting to see lslocks | grep DELE | wc go down. It’s not. >>> It’s staying around 1850. >> >> All it should do is prevent giving out *new* delegations. >> >> Best is to set that sysctl on system startup before nfsd starts. >> >>>> On Aug 9, 2021, at 2:30 PM, Timothy Pearson >>>> wrote: >>>> >>>> FWIW that's *exactly* what we see. Eventually, if the server is >>>> left alone for enough time, even the login system stops responding >>>> -- it's as if the I/O subsystem degrades and eventually blocks >>>> entirely. >> >> That's pretty common behavior across a variety of kernel bugs. So on >> its own it doesn't mean the root cause is the same. >> > > --b.