Re: UBSAN: run-time undefined behavior sanity checker

[Dave Jones]

On Mon, Feb 01, 2016 at 07:08:46PM +0300, Andrey Ryabinin wrote:

 > >  > > tried it on hangs the same way, really early.  Any thoughts on how to chase this down ?
 > >  > Try to disable instrumentation for early code, like in the patch bellow.
 > > This didn't help.
 > 
 > So after I enabled UBSAN_ALIGNMENT in your config, the kernel didn't boot.
 > That is because unaligned access happens before lockdep_init() so ubsan callback takes the
 > spinlock before locked_init() which is not allowed.
 
 > Could you try it without CONFIG_DEBUG_LOCKDEP?
 > Or alternatively with patch like this:

Tried with the patch, seems to work fine now.

thanks,
	Dave