The printf should have a lock?

[2544632b]

Chaos output when with —enable-kvm, I fix it by adding a lock for printf.

[travisg]

Well, it's actually much more difficult than that, since printf can be called from interrupt handlers or even inside critical locks. The only mechanism that would work is some sort of spinlock but then that's terribly inefficient.

The solution I've been thinking about is on SMP capable (or otherwise 'big' systems) have a per thread buffer that when it's filled is dumped, with a console lock being held. If a printf is called from interrupt context, it'll just print right there, which may chop a line, but in general prnting from IRQ handlers is debug only and should generally be avoided.

[2544632b]

🤔