nmi.c has two variables, nmi_watchdog and nmi_watchdog_enabled. The former can be set on the boot command line. However, there's also a /proc/sys/kernel/nmi_watchdog but confusingly this edits nmi_watchdog_enabled and not the command line nmi_watchdog. Can the sysctl filename be changed to nmi_watchdog_enabled to match the code and make it clear that the boot-time nmi_watchdog isn't being changed? Frequent advice to users suffering hard hang-ups is to enable the nmi_watchdog, there's evidence that them, and me, have to then puzzle over why writing 2 to /proc/sys/kernel/nmi_watchdog isn't working.
I'll reassign this to platform_i386@kernel-bugs.osdl.org. We'd prefer not to change the filename - it's now part of the kernel->userspace interface and changing that is a big deal. Is there some other way?
OK, fair enough. Is the boot command line more flexible in changing? Perhaps its nmi_watchdog and the underlying nmi.c:nmi_watchdog variable could be renamed but I suspect not, in which case I can't see anything that can be done apart from user education.
there are two separate concepts here: nmi_watchdog_enabled is the "user wish". nmi_watchdog is the reality the kernel is able to offer. Sometimes the two differ: user wants to set nmi_watchdog=1 but that's not possible. Ideally it should be possible to enable all NMI watchdog variants both from the command line and from the sysctl - patches are welcome. (and it's not a matter of changing a variable name)
(In reply to comment #3) > there are two separate concepts here: > > nmi_watchdog_enabled is the "user wish". > > nmi_watchdog is the reality the kernel is able to offer. > > Sometimes the two differ: user wants to set nmi_watchdog=1 but that's not > possible. Ideally it should be possible to enable all NMI watchdog variants > both from the command line and from the sysctl - patches are welcome. (and > it's > not a matter of changing a variable name) > Is anybody working on this? If not I want work on this.
Closing old stale bugs