I bisected these CONFIG_THUMB2_KERNEL boot failures:

0db805aa8c96f0eac0cb5bc6688999212fb5f5d3 is the first bad commit
commit 0db805aa8c96f0eac0cb5bc6688999212fb5f5d3
Author: Russell King <rmk+kernel@arm.linux.org.uk>
Date:   Wed Aug 19 20:40:41 2015 +0100

    ARM: software-based priviledged-no-access support
    
    Provide a software-based implementation of the priviledged no access
    support found in ARMv8.1.
    
    Userspace pages are mapped using a different domain number from the
    kernel and IO mappings.  If we switch the user domain to "no access"
    when we enter the kernel, we can prevent the kernel from touching
    userspace.
    
    However, the kernel needs to be able to access userspace via the
    various user accessor functions.  With the wrapping in the previous
    patch, we can temporarily enable access when the kernel needs user
    access, and re-disable it afterwards.
    
    This allows us to trap non-intended accesses to userspace, eg, caused
    by an inadvertent dereference of the LIST_POISON* values, which, with
    appropriate user mappings setup, can be made to succeed.  This in turn
    can allow use-after-free bugs to be further exploited than would
    otherwise be possible.
    
    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

:040000 040000 3ba2c3c3777b2d1ea6f68002a79eb9bc8162d64a 0bfc56928dfe41e4fd1d1180d1969a4ecb12b33b M	arch
bisect run success
git bisect start
# bad: [512450361ea46ed5a8c5d81f507fef094181ab91] Add linux-next specific files for 20150825
git bisect bad 512450361ea46ed5a8c5d81f507fef094181ab91
# good: [c13dcf9f2d6f5f06ef1bf79ec456df614c5e058b] Linux 4.2-rc8
git bisect good c13dcf9f2d6f5f06ef1bf79ec456df614c5e058b
# bad: [ad445f1d179a661c51bb345704399ca57ebb1824] Merge remote-tracking branch 'drm/drm-next'
git bisect bad ad445f1d179a661c51bb345704399ca57ebb1824
# bad: [c41e15b28185d930f98a4b66c3f9397555d06d64] Merge remote-tracking branch 'kbuild/for-next'
git bisect bad c41e15b28185d930f98a4b66c3f9397555d06d64
# bad: [707f9e14767d7a323bb51f3b92bb0c670288b3dd] Merge remote-tracking branch 'mips/mips-for-linux-next'
git bisect bad 707f9e14767d7a323bb51f3b92bb0c670288b3dd
# good: [2ee33987978459a8e3c9572c69d34195367a2995] Merge branch 'next/dt' into for-next
git bisect good 2ee33987978459a8e3c9572c69d34195367a2995
# bad: [b423c2b274ac4ec9bcbdcd6f33ea2e7d798eb700] Merge remote-tracking branch 'samsung/for-next'
git bisect bad b423c2b274ac4ec9bcbdcd6f33ea2e7d798eb700
# good: [332d55b295f72be7b7b91bf119719c6b61f4777c] arm-soc: document merges
git bisect good 332d55b295f72be7b7b91bf119719c6b61f4777c
# bad: [537ad7e742dea3440925cbee2d3743e72b25b192] Merge remote-tracking branch 'at91/at91-next'
git bisect bad 537ad7e742dea3440925cbee2d3743e72b25b192
# bad: [555d3b763e4bd9a87eb4e6817cf40b4591cd3cc5] Merge branch 'devel-stable' into for-next
git bisect bad 555d3b763e4bd9a87eb4e6817cf40b4591cd3cc5
# good: [96231b2686b53f71838a335bdc404cb5285d1a01] ARM: 8419/1: dma-mapping: harmonize definition of DMA_ERROR_CODE
git bisect good 96231b2686b53f71838a335bdc404cb5285d1a01
# bad: [8909f06cf8634947a48caa651f77620f6345a751] Merge branches 'cleanup', 'fixes', 'fiq' (early part), 'misc', 'omap-barrier', 'pcmcia' and 'uaccess' into for-next
git bisect bad 8909f06cf8634947a48caa651f77620f6345a751
# bad: [0db805aa8c96f0eac0cb5bc6688999212fb5f5d3] ARM: software-based priviledged-no-access support
git bisect bad 0db805aa8c96f0eac0cb5bc6688999212fb5f5d3
# good: [3c2aed5b28819564e1a07b4686bd89802bcc4d6b] ARM: domains: get rid of manager mode for user domain
git bisect good 3c2aed5b28819564e1a07b4686bd89802bcc4d6b
# good: [1fb6755f16872ad256c18cce2830f9087502dffd] ARM: domains: remove DOMAIN_TABLE
git bisect good 1fb6755f16872ad256c18cce2830f9087502dffd
# good: [85f3dc0c51564aa13d6fef06226ceb00058f208e] ARM: entry: provide uaccess assembly macro hooks
git bisect good 85f3dc0c51564aa13d6fef06226ceb00058f208e
# first bad commit: [0db805aa8c96f0eac0cb5bc6688999212fb5f5d3] ARM: software-based priviledged-no-access support

Cheers,

Tyler