On Sun, Jul 12, 2020 at 08:51:26PM -0700, Linus Torvalds wrote:
Maybe saying "doing the pmd copies for the initial stack isn't important, so let's just note this as a special case and get rid of the WARN_ON()" might be an alternative solution.
Personally, I feel it is better to keep the warning just so in the future we can detect any bugs.
I don't disagree, the warning didn't happen to find a bug now, but it did fine a case we might be able to do better.
So now that I feel we understand the issue, and it's not a horrible problem, just a (very hard to trigger) warning, I don't think there's any huge hurry.
I think think I will - for now - change the WARN_ON() to WARN_ON_ONCE() (so that it doesn't floow the logs if somebody triggers this odd special case this malisiously), and add a note about how this happens to the code for posterito.
And if/when you figure out a better way to fix it, we can update the note.
Ok?
Yes, that sounds great to me.
thanks,
- Joel