r350484 and ASLR enabled - init died (signal 6, exit 0)

[Konstantin Belousov]

On Mon, Aug 05, 2019 at 08:10:43PM +0200, Trond Endrestøl wrote:
> On Mon, 5 Aug 2019 06:02-0700, David Wolfskill wrote:
> 
> > On Mon, Aug 05, 2019 at 02:53:04PM +0200, Trond Endrestøl wrote:
> > > Hi,
> > > 
> > > Has anyone else noticed the kernel being unable to spawn init lately?
> > > 
> > > All I get is:
> > > 
> > > init died (signal 6, exit 0)
> > > panic: Going nowhere without my init!
> > > 
> > > /sbin/init hasn't had any changes in 4 months, and is present in /sbin 
> > > in the new BE.
> > > 
> > > I've tried and failed in VBox at home this weekend, and in Citrix 
> > > Hypervisor 8 at $WORK today. I think we can rule out the hypervisors.
> > > 
> > > Last known working revision is r350400.
> > > 
> > > There are numerous kernel changes between r350400 and r350583. I'll 
> > > try each revision in succession and see if I can identify any 
> > > culprits.
> > > ...
> > 
> > I have not seen the behavior in question; my last update was from
> > r350566 to r350584 (and was quite uneventful).
> > 
> > In each case, a "real machine" was used (laptop & a build machine).
> 
> After more trial and error, r350484 is the culprit for Citrix 
> Hypervisor 8.
> 
> I have these lines in /boot/loader.conf:
> 
> kern.elf32.aslr.enable="1"
> kern.elf32.aslr.pie_enable="1"
> 
> kern.elf64.aslr.enable="1"
> kern.elf64.aslr.pie_enable="1"
> 
> r350483 works like a charm, and so does r350484 iff I disable ASLR.
> 
> Reenabling ASLR and setting kern.elf{64,32}.aslr.stack_gap to zero has 
> no effect.
> 
> I've cc'd kib@ on this one.
> 
> I'm going home and see if VBox 6.0.10 exhibits the same behaviour.

Try r350608. There was a mis-merge in the committed patch (more serious
part), and some limits were not applied, which I did not see in my
testing due to the mismatch between stock FreeBSD and my testing
environment.