multi_v7_defconfig + CONFIG_KASAN=y boot failure

[nathanchance]

This is mainly for tracking/visibility. Beginning of the upstream report and discussion: https://lore.kernel.org/linux-arm-kernel/20201030013228.GA2519055@ubuntu-m3-large-x86/

TL;DR: Something is going wrong with futex_init, which appears related to #325, as @arndb 's noinline patch fixes it.

$ git fetch git://git.armlinux.org.uk/~rmk/linux-arm.git for-next && git checkout FETCH_HEAD

$ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- LLVM=1 O=out distclean defconfig

$ scripts/config --file out/.config -e KASAN

$ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- LLVM=1 O=out olddefconfig zImage

$ ~/cbl/github/boot-utils/boot-qemu.sh -a arm32_v7 -k out -t 15s
...
+ timeout --foreground 30s unbuffer qemu-system-arm ...
+ RET=124
...

[nathanchance]

This appears to be resolved now that #325 is.