RE: Removing Mandatory Locks

[David Laight]

From: Linus Torvalds
> Sent: 19 August 2021 23:33
> 
> On Thu, Aug 19, 2021 at 2:43 PM Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> >
> > What sort of big, ugly warning did you have in mind?
> 
> I originally thought WARN_ON_ONCE() just to get the distro automatic
> error handling involved, but it would probably be a big problem for
> the people who end up having panic-on-warn or something.

Even panic-on-oops is a PITA.
Took us weeks to realise that a customer system that was randomly
rebooting was 'just' having a boring NULL pointer access.
 
> So probably just a "make it a big box" thing that stands out, kind of
> what lockdep etc does with
> 
>         pr_warn("======...====\n");
> 
> around the messages..
> 
> I don't know if distros have some pattern we could use that would end
> up being something that gets reported to the user?

Will users even see it?
A lot of recent distro installs try very hard to hide all the kernel
messages.
OTOH I guess '-o mand' is unlikely to be set on any of those systems.

	David

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