Greeting,

FYI, we noticed the following commit (built with gcc-9):

commit: 03c44acf0b66a03248cd793f8f796477027a567f ("seq_read: move count check against iov_iter_count after calling op show")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git Xin-Long/seq_read-move-count-check-against-iov_iter_count-after-calling-op-show/20210125-193346


in testcase: xfstests
version: xfstests-x86_64-73c0871-1_20210114
with following parameters:

	disk: 4HDD
	fs: xfs
	test: generic-group-29
	ucode: 0xe2

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: 4 threads Intel(R) Xeon(R) CPU E3-1225 v5 @ 3.30GHz with 16G memory

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 <oliver.sang@intel.com>

2021-01-29 02:25:47 export TEST_DIR=/fs/sda1
2021-01-29 02:25:47 export TEST_DEV=/dev/sda1
2021-01-29 02:25:47 export FSTYP=xfs
2021-01-29 02:25:47 export SCRATCH_MNT=/fs/scratch
2021-01-29 02:25:47 mkdir /fs/scratch -p
2021-01-29 02:25:47 export SCRATCH_DEV=/dev/sda4
2021-01-29 02:25:47 export SCRATCH_LOGDEV=/dev/sda2
2021-01-29 02:25:47 sed "s:^:generic/:" //lkp/benchmarks/xfstests/tests/generic-group-29
2021-01-29 02:25:47 ./check generic/580 generic/581 generic/582 generic/583 generic/584 generic/585 generic/586 generic/587 generic/588 generic/589 generic/590 generic/591 generic/592 generic/593 generic/594 generic/595 generic/596 generic/597 generic/598 generic/599
FSTYP         -- xfs (debug)
PLATFORM      -- Linux/x86_64 lkp-skl-d06 5.11.0-rc5-00001-g03c44acf0b66 #1 SMP Thu Jan 28 19:24:48 CST 2021
MKFS_OPTIONS  -- -f -bsize=4096 /dev/sda4
MOUNT_OPTIONS -- /dev/sda4 /fs/scratch

generic/580	[not run] No encryption support for xfs
generic/581	[not run] No encryption support for xfs
generic/582	[not run] No encryption support for xfs
generic/583	[not run] No encryption support for xfs
generic/584	[not run] No encryption support for xfs
generic/585	 3s
generic/586	 3s
generic/587	 3s
generic/588	[not run] Reflink not supported by scratch filesystem type: xfs
generic/589	- output mismatch (see /lkp/benchmarks/xfstests/results//generic/589.out.bad)
    --- tests/generic/589.out	2021-01-14 07:40:58.000000000 +0000
    +++ /lkp/benchmarks/xfstests/results//generic/589.out.bad	2021-01-29 02:26:25.977759221 +0000
    @@ -8,6 +8,7 @@
     mpA/dir SCRATCH_DEV
     mpC SCRATCH_DEV
     mpC SCRATCH_DEV
    +mpC SCRATCH_DEV
     mpC/dir SCRATCH_DEV
     mpC/dir SCRATCH_DEV
     ======
    ...
    (Run 'diff -u /lkp/benchmarks/xfstests/tests/generic/589.out /lkp/benchmarks/xfstests/results//generic/589.out.bad'  to see the entire diff)
generic/590	[not run] mount failed, kernel doesn't support realtime?
generic/591	 1s
generic/592	[not run] No encryption support for xfs
generic/593	[not run] No encryption support for xfs
generic/594	- output mismatch (see /lkp/benchmarks/xfstests/results//generic/594.out.bad)
    --- tests/generic/594.out	2021-01-14 07:40:58.000000000 +0000
    +++ /lkp/benchmarks/xfstests/results//generic/594.out.bad	2021-01-29 02:26:31.749759744 +0000
    @@ -5,31 +5,31 @@
     *** Report for group quotas on device SCRATCH_DEV
     Block grace time: DEF_TIME; Inode grace time: DEF_TIME
     *** Report for project quotas on device SCRATCH_DEV
    -Block grace time: 00:10; Inode grace time: 00:20
    +Block grace time: DEF_TIME; Inode grace time: DEF_TIME
     
     2. set group quota timer
    ...
    (Run 'diff -u /lkp/benchmarks/xfstests/tests/generic/594.out /lkp/benchmarks/xfstests/results//generic/594.out.bad'  to see the entire diff)
generic/595	[not run] No encryption support for xfs
generic/596	 3s
generic/597	 1s
generic/598	 1s
generic/599	 3s
Ran: generic/580 generic/581 generic/582 generic/583 generic/584 generic/585 generic/586 generic/587 generic/588 generic/589 generic/590 generic/591 generic/592 generic/593 generic/594 generic/595 generic/596 generic/597 generic/598 generic/599
Not run: generic/580 generic/581 generic/582 generic/583 generic/584 generic/588 generic/590 generic/592 generic/593 generic/595
Failures: generic/589 generic/594
Failed 2 of 20 tests




To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp install                job.yaml  # job file is attached in this email
        bin/lkp split-job --compatible job.yaml
        bin/lkp run                    compatible-job.yaml



Thanks,
Oliver Sang