Re: [Qemu-devel] rcu kicking CPU threads before they're set up...

[Paolo Bonzini]

On 11/03/2015 11:23, Peter Maydell wrote:
> I noticed this while I was trying to debug something and so was
> single stepping through the CPU realize function.
> 
> The rcu thread seems to get set up and try to start working too
> early in QEMU's initialization process. Specifically, it can try
> to do things before we've completed the creation and init of all
> the CPUs: I'm seeing call_rcu_thread() calling qemu_mutex_lock_iothread()
> calling  qemu_cpu_kick_thread() before we've even finished actually
> creating and realizing the CPU objects. This segfaults because
> cpu->thread isn't set yet.

Should be fixed by now:

commit 6b49809c597331803ea941eadda813e5bb4e8fe2
Author: Paolo Bonzini <address@hidden>
Date:   Fri Feb 27 19:58:23 2015 +0100

    cpus: fix deadlock and segfault in qemu_mutex_lock_iothread

commit 21618b3e55ad2c6fede0bffcaea466091811ce59
Author: Paolo Bonzini <address@hidden>
Date:   Fri Feb 27 20:01:03 2015 +0100

    cpus: be more paranoid in avoiding deadlocks


Paolo