Hello, I have a Dell Inspiron 15-5547 laptop, with systemd configured to set the watchdog to a 2-minute expiry (due to reasons): # /etc/systemd/system.conf [Manager] RuntimeWatchdogSec=2min So far this setting has worked without problems (including kernels 5.12.15 and 5.13.1); however, with kernel 5.13.4 the system inevitably reboots after a few minutes of uptime. I have tracked the issue down to commit 5e65819a006e "watchdog: iTCO_wdt: Account for rebooting on second timeout" in the 5.13.x branch (commit cb011044e34c upstream). There are no unexpected reboots when running 5.13.4 with this commit reverted. Indeed with the original 5.13.4 kernel, `wdctl` always reports "Timeleft:" counting down from 60 seconds (sometimes very nearly reaching 0), even though "Timeout" is still reported to be 120. (systemd pokes the watchdog as part of its main loop, trying to so approximately "between 1/4 and 1/2" of the configured interval. According to wdctl these pings usually happen every 35-50 seconds but sometimes nearly at the 60-second mark, and thanks to the kernel now also dividing the requested expiry by /2 which systemd is unaware of, sometimes this ends up being a *very* close race to 0.) This is a Haswell-era machine (i7-4510U) and seems to have a "version 0" watchdog: Jul 26 11:34:04 archlinux kernel: Linux version 5.13.4-arch2-1 (linux@archlinux) (gcc (GCC) 11.1.0, GNU ld (GNU Binutils) 2.36.1) #1 SMP PREEMPT Thu, 22 Jul 2021 20:46:28 +0000 Jul 26 11:34:14 frost kernel: iTCO_vendor_support: vendor-support=0 Jul 26 11:34:14 frost kernel: iTCO_wdt iTCO_wdt.3.auto: Found a Lynx Point_LP TCO device (Version=2, TCOBASE=0x1860) Jul 26 11:34:14 frost systemd[1]: Using hardware watchdog 'iTCO_wdt', version 0, device /dev/watchdog Jul 26 11:34:14 frost systemd[1]: Set hardware watchdog to 2min. Jul 26 11:34:14 frost kernel: iTCO_wdt iTCO_wdt.3.auto: initialized. heartbeat=30 sec (nowayout=0) -- Mantas Mikulėnas
