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

commit: ddf30cf03fb53b9a0ad0f355a69dbedf416edde9 ("btrfs: extent-tree: Use btrfs_ref to refactor add_pinned_bytes()")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

in testcase: xfstests
with following parameters:

	disk: 4HDD
	fs: btrfs
	test: generic-quick2

test-description: xfstests is a regression test suite for xfs and other files ystems.
test-url: git://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git


on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 4G

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


FSTYP         -- btrfs
PLATFORM      -- Linux/x86_64 vm-snb-4G-727 5.1.0-rc7-00188-gddf30cf
MKFS_OPTIONS  -- /dev/vdb
MOUNT_OPTIONS -- /dev/vdb /fs/scratch

generic/088 2s
generic/089 14s
generic/090 1s
generic/091 19s
generic/092 3s
generic/098 4s
generic/100 18s
generic/101 0s
generic/102- output mismatch (see /lkp/benchmarks/xfstests/results//generic/102.out.bad)
    --- tests/generic/102.out2019-05-09 15:46:08.000000000 +0800
    +++ /lkp/benchmarks/xfstests/results//generic/102.out.bad2019-05-10 09:32:39.267250059 +0800
    @@ -1,21 +1,21 @@
     QA output created by 102
     wrote 838860800/838860800 bytes at offset 0
     XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
    -wrote 838860800/838860800 bytes at offset 0
    +wrote 109576192/838860800 bytes at offset 0
     XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
     wrote 838860800/838860800 bytes at offset 0
    ...
    (Run 'diff -u /lkp/benchmarks/xfstests/tests/generic/102.out /lkp/benchmarks/xfstests/results//generic/102.out.bad'  to see the entire diff)
generic/103 1s
generic/104 1s
generic/105 0s
generic/106 1s
generic/107 1s
generic/109 1s
generic/120 16s
generic/123  1s
generic/124  4s
generic/126  1s
generic/129  6s
generic/130 13s

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

To reproduce:

        # build kernel
	cd linux
	cp config-5.1.0-rc7-00188-gddf30cf .config
	make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 olddefconfig
	make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 prepare
	make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 modules_prepare
	make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 SHELL=/bin/bash
	make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 bzImage


        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz
	bin/lkp qemu -k <bzImage> -m modules.cgz job-script # job-script is attached in this email




Thanks,
Rong Chen