linux-next crash during very early boot

From: Valdis Kletnieks
Date: Wed Apr 13 2016 - 20:29:57 EST


I'm seeing my laptop crash/wedge up/something during very early
boot - before it can write anything to the console. Nothing in pstore,
need to hold down the power button for 6 seconds and reboot.

git bisect points at:

commit 7a6bacb133752beacb76775797fd550417e9d3a2
Author: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Date: Thu Apr 7 13:59:39 2016 +1000

mm/slab: factor out kmem_cache_node initialization code

It can be reused on other place, so factor out it. Following patch will
use it.


Not sure what the problem is - the logic *looks* ok at first read. The
patch *does* remove a spin_lock_irq() - but I find it difficult to
believe that with it gone, my laptop is able to hit the race condition
the spinlock protects against *every single boot*.

The only other thing I see is that n->free_limit used to be assigned
every time, and now it's only assigned at initial creation.

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