Re: rms_rlock with non-sleepable locks held
Date: Sat, 16 May 2026 14:55:44 UTC
On Sat, May 16, 2026 at 03:45:39PM +0200, Dag-Erling Smørgrav wrote: > Konstantin Belousov <kostikbel@gmail.com> writes: > > Dag-Erling Smørgrav <des@FreeBSD.org> writes: > > > On recent main with a debugging kernel, I am unable to build > > > anything as the system slows to a crawl while the console is > > > inundated with stack traces: [...] > > I already posted the patch below somewhere, but did not get a response. > > The patch made no difference. > > FWIW what triggers the problem is running tail -F on the build log, > which I always do when building. Tailing a file which is being written > to triggers it on every write, but even tailing an empty file triggers > it about once per second. > > So for now I'm able to build, as long as I don't tail the log... > ... I am a bit puzzled, as from the description, I would expect to see similar behavior, but I do not. I am tracking head (and stable/15) daily, on a set of 5 machines: * a headless build machine, AMD EPYC 7502P 32-Core Processor, with GENERIC kernel; * 3 Dell laptops of varying vintages with 4-core Intel CPUs with a lightly-customized kernel based on GENERIC; * 1 Thinkpad T14s, also with an Intel CPU, with GENERIC kernel. The Thinkpad is completely ZFS-based; the others are UFS(+SU)-based (but the headless build machine uses ZFS for ports & package-building (using poudriere-devel)). Each is amd64. Each uses meta-mode. Two of the Dell laptops use ccache. Each machine has its own private local mirror of the FreeBSD.org src, ports, & doc respoistories. The build machine syncs from git.freebsd.org; the others sync from it (unless I'm traveling with one of them). In each case, I am logging in to each machine from a different (6th) one, on which I run net/omnitty to mux the ssh sessions; on each, I run tmux; within the tmux session, I do the builds within script(1). I login to each again (from another omnitty session) to run tail -9999999f $logfile | egrep '^(>>|(make\[[0-9]+\]|ld):)' to track progress. I have found it speeds things up a bit to detch the tmux sessions, so I don't have 5 machines' worth of build-chatter spewing at one poor laptop over a wireless link. :-} The last few builds of head were: main-n285812-bcecad2c24aa: Tue May 12 11:07:43 UTC 2026 main-n285848-1729d2f741a1: Wed May 13 11:10:51 UTC 2026 main-n285902-b8606c3406ea: Thu May 14 11:47:03 UTC 2026 main-n285916-e0c3d21e3b43: Fri May 15 10:52:11 UTC 2026 main-n285928-183633079178: Sat May 16 10:40:02 UTC 2026 More details are at https://www.catwhisker.org/~david/FreeBSD/history/, in case that might be of interest. Peace, david -- David H. Wolfskill david@catwhisker.org See https://www.catwhisker.org/~david/publickey.gpg for my public key.