FYI, we noticed the following commit (built with gcc-7):

commit: 6413f852ce086c0f95817012c08d481ce24d8b1a ("apparmor: add proc subdir to attrs")
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master

in testcase: ltp
with following parameters:

	disk: 1HDD
	fs: xfs
	test: fs-02

test-description: The LTP testsuite contains a collection of tools for testing the Linux kernel and related features.
test-url: http://linux-test-project.github.io/


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>


<<<test_start>>>
tag=proc01 stime=1581538074
cmdline="proc01 -m 128"
contacts=""
analysis=exit
<<<test_output>>>
proc01      0  TINFO  :  /proc/sys/fs/binfmt_misc/register: is write-only.
proc01      0  TINFO  :  /proc/sys/net/ipv6/conf/all/stable_secret: known issue: errno=EIO(5): Input/output error
proc01      0  TINFO  :  /proc/sys/net/ipv6/conf/default/stable_secret: known issue: errno=EIO(5): Input/output error
proc01      0  TINFO  :  /proc/sys/net/ipv6/conf/eth0/stable_secret: known issue: errno=EIO(5): Input/output error
proc01      0  TINFO  :  /proc/sys/net/ipv6/conf/lo/stable_secret: known issue: errno=EIO(5): Input/output error
proc01      0  TINFO  :  /proc/kmsg: known issue: errno=EAGAIN/EWOULDBLOCK(11): Resource temporarily unavailable
proc01      0  TINFO  :  /proc/sysrq-trigger: is write-only.
proc01      0  TINFO  :  /proc/self/task/2646/mem: known issue: errno=EIO(5): Input/output error
proc01      0  TINFO  :  /proc/self/task/2646/clear_refs: is write-only.
proc01      0  TINFO  :  /proc/self/task/2646/pagemap: reached maxmbytes (-m)
proc01      1  TFAIL  :  proc01.c:397: read failed: /proc/self/task/2646/attr/apparmor/current: errno=EINVAL(22): Invalid argument
proc01      2  TFAIL  :  proc01.c:397: read failed: /proc/self/task/2646/attr/apparmor/prev: errno=EINVAL(22): Invalid argument
proc01      3  TFAIL  :  proc01.c:397: read failed: /proc/self/task/2646/attr/apparmor/exec: errno=EINVAL(22): Invalid argument
proc01      0  TINFO  :  /proc/self/mem: known issue: errno=EIO(5): Input/output error
proc01      0  TINFO  :  /proc/self/clear_refs: is write-only.
proc01      0  TINFO  :  /proc/self/pagemap: reached maxmbytes (-m)
proc01      4  TFAIL  :  proc01.c:397: read failed: /proc/self/attr/apparmor/current: errno=EINVAL(22): Invalid argument
proc01      5  TFAIL  :  proc01.c:397: read failed: /proc/self/attr/apparmor/prev: errno=EINVAL(22): Invalid argument
proc01      6  TFAIL  :  proc01.c:397: read failed: /proc/self/attr/apparmor/exec: errno=EINVAL(22): Invalid argument
proc01      7  TFAIL  :  proc01.c:466: readproc() failed with 6 errors.
<<<execution_status>>>
initiation_status="ok"
duration=1 termination_type=exited termination_id=1 corefile=no
cutime=7 cstime=89
<<<test_end>>>



To reproduce:

        # build kernel
	cd linux
	cp config-5.5.0-rc5-00005-g6413f852ce086 .config
	make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage modules
	make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 INSTALL_MOD_PATH=<mod-install-dir> modules_install
	cd <mod-install-dir>
	find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz


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



Thanks,
Rong Chen