Greeting,

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

commit: c0aaf9b7a114f6b75e0da97be7d99c102347a751 ("btrfs: switch to iomap_dio_rw() for dio")
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master


in testcase: ltp
with following parameters:

	disk: 1HDD
	fs: btrfs
	test: dio-00
	ucode: 0x21

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: 8 threads Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz 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>


in attached kmsg.xz for c0aaf9b7a1

user  :notice: [   74.917829] diotest03    0  TINFO  :  3 testblocks 100 iterations with 1 children completed
user  :notice: [   74.919689] <<<execution_status>>>
user  :notice: [   74.921486] initiation_status="ok"
user  :notice: [   74.924044] duration=3 termination_type=exited termination_id=0 corefile=no
user  :notice: [   74.925798] cutime=1 cstime=4
user  :notice: [   74.927515] <<<test_end>>>
user  :notice: [   74.929115] <<<test_start>>>
user  :notice: [   74.930985] tag=dio04 stime=1598784407
user  :notice: [   74.932697] cmdline="diotest4"    <----- start to stuck after diotest4 starting
user  :notice: [   74.934268] contacts=""
user  :notice: [   74.935860] analysis=exit
user  :notice: [   74.937556] <<<test_output>>>
user  :notice: [   90.977611] IPMI BMC is not supported on this machine, skip bmc-watchdog setup!
user  :notice: [ 3690.978134] Sun Aug 30 11:47:43 UTC 2020 detected soft_timeout    <----- until soft_timeout (1h) detected by robot

below is from attached parent kmsg-b77407c36a.xz

user  :notice: [   74.876938] diotest03    0  TINFO  :  3 testblocks 100 iterations with 1 children completed
user  :notice: [   74.878759] <<<execution_status>>>
user  :notice: [   74.880533] initiation_status="ok"
user  :notice: [   74.883052] duration=3 termination_type=exited termination_id=0 corefile=no
user  :notice: [   74.884734] cutime=1 cstime=2
user  :notice: [   74.886381] <<<test_end>>>
user  :notice: [   74.887971] <<<test_start>>>
user  :notice: [   74.889798] tag=dio04 stime=1598804724
user  :notice: [   74.891494] cmdline="diotest4"
user  :notice: [   74.893005] contacts=""
user  :notice: [   74.894584] analysis=exit
user  :notice: [   74.896235] <<<test_output>>>
user  :notice: [   74.898323] diotest4    1  TPASS  :  Negative Offset    <----- diotest4 start to run ...
user  :notice: [   74.900214] diotest4    2  TPASS  :  removed
...
user  :notice: [   74.941552] diotest4    0  TINFO  :  15 testblocks completed    <----- ... and finish quickly
user  :notice: [   74.943551] <<<execution_status>>>
user  :notice: [   74.945461] initiation_status="ok"
user  :notice: [   74.948140] duration=0 termination_type=exited termination_id=0 corefile=no
user  :notice: [   74.950018] cutime=0 cstime=0
user  :notice: [   74.951775] <<<test_end>>>
user  :notice: [   74.953532] <<<test_start>>>
user  :notice: [   74.955426] tag=dio05 stime=1598804724
user  :notice: [   74.957168] cmdline="diotest5"
...
user  :notice: [  388.377363] INFO: ltp-pan reported all tests PASS   <----- all ltp test finish within 388s
user  :notice: [  388.378190] LTP Version: 20200515-110-gd2768c84e

user  :notice: [  388.379916]        ###############################################################
user  :notice: [  388.380922]             Done executing testcases.
user  :notice: [  388.382040]             LTP Version:  20200515-110-gd2768c84e
user  :notice: [  388.383625]        ###############################################################

except kernel, there is no test env changes between parent and c0aaf9b7a1.
the kconfig used for parent and c0aaf9b7a1 is identical as attached.


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 run     job.yaml



Thanks,
Oliver Sang