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From: Dave Jones <davej@codemonkey.org.uk>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: UBSAN: run-time undefined behavior sanity checker
Date: Mon, 1 Feb 2016 17:18:52 -0500	[thread overview]
Message-ID: <20160201221852.GA23344@codemonkey.org.uk> (raw)
In-Reply-To: <56AF830E.1050707@virtuozzo.com>

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

      reply	other threads:[~2016-02-01 22:18 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20160121205717.AF61F661293@gitolite.kernel.org>
2016-01-22  5:15 ` UBSAN: run-time undefined behavior sanity checker Dave Jones
2016-01-22 16:43   ` Andrey Ryabinin
2016-01-22 17:00     ` Dave Jones
2016-01-25 14:03       ` Andrey Ryabinin
     [not found]         ` <20160126165322.GA24364@codemonkey.org.uk>
2016-02-01 16:08           ` Andrey Ryabinin
2016-02-01 22:18             ` Dave Jones [this message]

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