Dnia 2021-03-15, o godz. 09:03:07 Rasmus Villemoes <[email protected]> napisał(a):
> On 09/03/2021 13.33, Rasmus Villemoes wrote: > > On 01/03/2021 16.11, Rasmus Villemoes wrote: > >> When the nowayout option is used with a watchdog device, busybox' > >> current behaviour of always doing a open/write magic char/close > >> sequence before the "real" open causes warning messages in the kernel > >> log: > >> > >> [ 16.212184] watchdog: watchdog0: nowayout prevents watchdog being > >> stopped! [ 16.212196] watchdog: watchdog0: watchdog did not stop! > >> > >> The latter may also appear by itself in case the watchdog is of the > >> type that cannot be stopped once started. > >> > >> These warnings can be somewhat ominous and distracting, so allow > >> configuring whether to use this open-write-close-open sequence rather > >> than just open. > > > > ping > > ping^2 > > Come to think of it, I actually think the open_twice feature should be > default n. It seems one might as well start the watchdog daemon with a > wrapper that does "printf 'V' > /dev/watchdog0; exec watchdog ...". But > either way, please consider this patch. > > Rasmus It seems that the open-write-close-open sequence has been introduced in busybox 1.28.0 by commit https://git.busybox.net/busybox/commit/?h=31c765081dc41f158786545fbea9294be4685bd2 AFAIU the commit message says that it is a kind of a workaround for some possible implementations of hardware watchdogs, which could enter wrong state when their supervisor in userspace is restarted (confused by close/open? I don't know). But it doesn't name any single example of an existing watchdog like that. In my case (softdog nowayout=1) that "fix" only adds: - bloat to busybox, and - annoying critical error message from kernel (yes, "watchdog: watchdog0: watchdog did not stop!" is at KERN_CRIT level) So I'm definitely for making the behaviour introduced by commit 31c765081dc41f158786545fbea9294be4685bd2 optional. -- _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
