Re: divide error in x86 and cputime

[Oleg Nesterov <oleg@redhat.com>]

On 07/07, Steven Rostedt wrote:
>
> On Mon, 7 Jul 2025 18:20:56 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > I would say this should never happen and if it does, let the kernel crash.
>
> >> [78250815.703852] CPU: 127 PID: 83435 Comm: killall Kdump: loaded Tainted: P           OE K   5.10.0 #1
>
> This happened on a 5.10 kernel with a proprietary module loaded, so
> honestly, if it can't be reproduced on a newer kernel without any
> proprietary modules loaded, I say we don't worry about it.

Yes, agreed, see my reply to myself.

Oleg.

> I also don't by the utime + stime overflowing a 64bit number.
>
>   2^64 / 2 = 2^63 = 9223372036854775808
>
> That would be:
>
>                                    minutes    days
>                                       v        v
>   9223372036854775808 / 1000000000 / 60 / 60 / 24 / 365.25 = 292.27
>                            ^               ^         ^
>                         ns -> sec       hours       years
>
> So the report says they have threads running for a very long time, it would
> still be 292 years of run time!
>
> -- Steve
>