Greeting,

FYI, we noticed the following commit (built with clang-11):

commit: 2f08469563550d15cb08a60898d3549720600eee ("rcu: Mark rcu_state.ncpus to detect concurrent writes")
https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git dev.2020.05.14c

in testcase: boot

on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 8G

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):




If you fix the issue, kindly add following tag
Reported-by: kernel test robot <rong.a.chen@intel.com>


[    0.054943] BRK [0x05204000, 0x05204fff] PGTABLE
[    0.061181] BRK [0x05205000, 0x05205fff] PGTABLE
[    0.062403] BRK [0x05206000, 0x05206fff] PGTABLE
[    0.065200] RAMDISK: [mem 0x7a247000-0x7fffffff]
[    0.067344] ACPI: Early table checksum verification disabled
BUG: kernel reboot-without-warning in boot stage

Elapsed time: 60

qemu-img create -f qcow2 disk-vm-snb-16-0 256G
qemu-img create -f qcow2 disk-vm-snb-16-1 256G


To reproduce:

        # build kernel
	cd linux
	cp config-5.7.0-rc2-00003-g2f08469563550 .config
	make HOSTCC=clang-11 CC=clang-11 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email



Thanks,
Rong Chen