Hi I am also seeing this problem. Am Dienstag, 18. September 2018, 15:46:15 CEST schrieb Guenter Roeck: > Please not only describe what you are doing, but also provide the complete > context. Specifically, > - Did this ever work ? I have not found a working kernel version. > If yes, what are working kernel versions ? I have tried different kernel version which where *not* working: patch-4.11.12-rt15 (with some Altera/Intel driver patches) 4.16.8-rt3 4.18-rc8-rt1 4.18.7-rt5 (with adxl372 iio patches and denali nand race fix reported on mainline) > - Is the watchdog device open ? Good point: The bootloader arms the watchdog. Then WATCHDOG_HANDLE_BOOT_ENABLED is enabled in kernel. But i forgot to let usermode take over. > - Does it make a difference if it is ? If i set RuntimeWatchdogSec=30 in /etc/systemd/system.conf (i.e. enable usermode watchdog) the problem seems to go away (at least i didn't had a reboot dony with my short testruns by now). > - What is the configured watchdog timeout (both from BIOS/ROMMON and in > Linux) ? 30s So to wrap up: i have the suspicion that the option WATCHDOG_HANDLE_BOOT_ENABLED without usermode taking over in Linux leads to some strange behaviour with preempt rt? Best regards Tim