[tun] 195624d9c2: ltp.ioctl03.fail

Hi Patrick,

We noticed that below commit introduced a new flag IFF_NO_CARRIER, and
looks like it triggers a failure of unknown flag in LTP testcase. We
don't have enough knowledge about whether this is a real issue, but the
test result is impacted by this change, so we send this report FYI and
cc LTP mailing list. Thanks.


Greeting,

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

commit: 195624d9c26b64c6856863da30ec578a790feec4 ("tun: support not enabling carrier in TUNSETIFF")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

in testcase: ltp
version: ltp-x86_64-14c1f76-1_20220929
with following parameters:

	disk: 1HDD
	fs: btrfs
	test: syscalls-03

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: 4 threads Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz (Skylake) with 32G memory

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


<<<test_start>>>
tag=ioctl03 stime=1664480977
cmdline="ioctl03"
contacts=""
analysis=exit
<<<test_output>>>
tst_test.c:1526: TINFO: Timeout per run is 0h 02m 30s
ioctl03.c:76: TINFO: Available features are: 0x7173
ioctl03.c:80: TPASS: TUN 0x1
ioctl03.c:80: TPASS: TAP 0x2
ioctl03.c:80: TPASS: NO_PI 0x1000
ioctl03.c:80: TPASS: ONE_QUEUE 0x2000
ioctl03.c:80: TPASS: VNET_HDR 0x4000
ioctl03.c:80: TPASS: MULTI_QUEUE 0x100
ioctl03.c:80: TPASS: IFF_NAPI 0x10
ioctl03.c:80: TPASS: IFF_NAPI_FRAGS 0x20
ioctl03.c:85: TFAIL: (UNKNOWN 0x40)

Summary:
passed   8
failed   1
broken   0
skipped  0
warnings 0
<<<execution_status>>>
initiation_status="ok"
duration=0 termination_type=exited termination_id=1 corefile=no
cutime=0 cstime=0
<<<test_end>>>


We also run this testcase on the parent commit of 195624d9c2, which is:

commit: 504c25cb76a9cb805407f7701b25a1fbd48605fa ("Merge tag 'net-6.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net")

Here we put the test log of commit 504c25cb76 as comparison:

<<<test_start>>>
tag=ioctl03 stime=1664418134
cmdline="ioctl03"
contacts=""
analysis=exit
<<<test_output>>>
tst_test.c:1526: TINFO: Timeout per run is 0h 02m 30s
ioctl03.c:76: TINFO: Available features are: 0x7133
ioctl03.c:80: TPASS: TUN 0x1
ioctl03.c:80: TPASS: TAP 0x2
ioctl03.c:80: TPASS: NO_PI 0x1000
ioctl03.c:80: TPASS: ONE_QUEUE 0x2000
ioctl03.c:80: TPASS: VNET_HDR 0x4000
ioctl03.c:80: TPASS: MULTI_QUEUE 0x100
ioctl03.c:80: TPASS: IFF_NAPI 0x10
ioctl03.c:80: TPASS: IFF_NAPI_FRAGS 0x20

Summary:
passed   8
failed   0
broken   0
skipped  0
warnings 0
<<<execution_status>>>
initiation_status="ok"
duration=0 termination_type=exited termination_id=0 corefile=no
cutime=0 cstime=0
<<<test_end>>>


If you fix the issue, kindly add following tag
| Reported-by: kernel test robot [off-list ref]
| Link: https://lore.kernel.org/r/202209301554.14621f76-yujie.liu@intel.com (local)


To reproduce:

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

        # if come across any failure that blocks the test,
        # please remove ~/.lkp and /lkp dir to run from a clean state.


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