SUMMARY *** Due to a problem with an unrelated software component (KMozillaHelper, see https://www.opensuse-forum.de/thread/66654-maximum-number-of-clients-reached-kmozillahelper/ (German, unfortunately)) I recently had many processes running and files open even right after booting my system. This did not cause any noticeable problems. I could start my IDE for software development, browse the web, etc. As far as I can tell the only issue I had is that I could not lock my screen, either via keyboard shortcut or by clicking the lock icon in the task bar. The error message in the logs was this: 2023-10-09T13:14:55.692681+02:00 laptop ksmserver[4361]: QProcessPrivate::createPipe: Cannot create pipe 0x7fbf90004b78 (Too many open files) 2023-10-09T13:14:55.699846+02:00 laptop ksmserver[4361]: kscreenlocker: Greeter Process not available Obviously this issue can be fixed by killing spurious kmozillahelper processes, but I do wonder why starting any other programm/process worked fine, and only the screen locker (a vital component!) could not be started. So please give this issue a thought before telling me to clean up my system ;-). PS executing /usr/lib/kscreenlocker_greet manually did work as expected! *** STEPS TO REPRODUCE 1. Open sufficiently many instances of KMozillaHelper 2. Try to lock the screen OBSERVED RESULT Screen did not lock EXPECTED RESULT Should have been locked SOFTWARE/OS VERSIONS KDE Plasma Version: 5.27.4 KDE Frameworks Version: 5.103.0 Qt Version: 5.15.8 ADDITIONAL INFORMATION My "ulimit" settings: $ ulimit -a core file size (blocks, -c) unlimited data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 127197 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 127197 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/3413
Git commit 5df2fe17c80eff6fdfcbd8385954e5b88a0f30c5 by Harald Sitter. Committed on 03/11/2023 at 12:47. Pushed by sitter into branch 'master'. ksmserver: cap the amount of app restorations when we restore more than ¼ of RLIMIT_NOFILE (default 1024) of a single application it is incredibly likely that this application is being defective (e.g. GUIless apps participating in session management but also in autostarting -- resulting in ever multiplying instances). when in excess, refuse to start **all** restorations of the application (NOTE: this is why we loop everything twice) M +89 -15 ksmserver/server.cpp https://invent.kde.org/plasma/plasma-workspace/-/commit/5df2fe17c80eff6fdfcbd8385954e5b88a0f30c5
Git commit 318e8b123954792886a1133396d014d59930dc4d by Harald Sitter. Committed on 03/11/2023 at 12:47. Pushed by sitter into branch 'master'. ksmserver: never allow ICE connections to exhaust RLIMIT_NOFILE At most use `RLIMIT_NOFILE - 128`; the remainder is reserved for other uses like invoking the lock screen, other sockets etc. to implement this there's a trivial ref count on KSMConnection. When too many references are active we'll force close connections again right after creation M +21 -0 ksmserver/server.cpp https://invent.kde.org/plasma/plasma-workspace/-/commit/318e8b123954792886a1133396d014d59930dc4d