Re: [PATCH net v3] tun/tap & vhost-net: make qdisc backpressure opt-in via IFF_BACKPRESSURE

Hello,

kernel test robot noticed "ltp.ioctl03.fail" on:

commit: 09154ff2072e36b86ba2d92d436b7f27df153ed1 ("[PATCH net v3] tun/tap &=
 vhost-net: make qdisc backpressure opt-in via IFF_BACKPRESSURE")
url: https://github.com/intel-lab-lkp/linux/commits/Simon-Schippers/tun-tap=
-vhost-net-make-qdisc-backpressure-opt-in-via-IFF_BACKPRESSURE/20260709-181=
234
base: https://git.kernel.org/cgit/linux/kernel/git/davem/net.git fabb881df3=
22da25442f98d23f5fa371e3c78ec4
patch link: https://lore.kernel.org/all/20260709095511.168235-1-simon.schip=
[email protected]/
patch subject: [PATCH net v3] tun/tap & vhost-net: make qdisc backpressure =
opt-in via IFF_BACKPRESSURE

in testcase: ltp
version:=20
with following parameters:

	disk: 1HDD
	fs: ext4
	test: syscalls-03



config: x86_64-rhel-9.4-ltp
compiler: gcc-14
test machine: 4 threads 1 sockets Intel(R) Core(TM) i3-3220 CPU @ 3.30GHz (=
Ivy Bridge) with 8G memory

(please refer to attached dmesg/kmsg for entire log/backtrace)



If you fix the issue in a separate patch/commit (i.e. not just a new versio=
n of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-lkp/[email protected]=
m


....

=1B[1;37mgetuid03: =1B[0m=1B[1;32mpass=1B[0m  (0.028s)
=1B[1;37mioctl03: =1B[0m=1B[1;31mfail=1B[0m  (0.047s)     <-----
=1B[1;37mioctl05: =1B[0m=1B[1;32mpass=1B[0m  (0.471s)

....

Execution time: 3m 35s

Disconnecting from SUT: default

Target information
=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=
=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=
=80=E2=94=80
Kernel:   Linux 7.2.0-rc1+ #1 SMP PREEMPT_DYNAMIC Sun Jul 12 07:25:38 CST 2=
026
Cmdline:  ip=3D::::lkp-ivb-d04::dhcp
          root=3D/dev/ram0
          RESULT_ROOT=3D/result/ltp/1HDD-ext4-syscalls-03/lkp-ivb-d04/debia=
n-13-x86_64-20250902.cgz/x86_64-rhel-9.4-ltp/gcc-14/09154ff2072e36b86ba2d92=
d436b7f27df153ed1/0
          BOOT_IMAGE=3D/pkg/linux/x86_64-rhel-9.4-ltp/gcc-14/09154ff2072e36=
b86ba2d92d436b7f27df153ed1/vmlinuz-7.2.0-rc1+
          branch=3Dlinux-devel/devel-hourly-20260709-190759
          job=3D/lkp/jobs/scheduled/lkp-ivb-d04/ltp-1HDD-ext4-syscalls-03-d=
ebian-13-x86_64-20250902.cgz-09154ff2072e-20260712-19649-tc8bu6-0.yaml
          user=3Dlkp
          ARCH=3Dx86_64
          kconfig=3Dx86_64-rhel-9.4-ltp
          commit=3D09154ff2072e36b86ba2d92d436b7f27df153ed1
          intremap=3Dposted_msi
          max_uptime=3D7200
          LKP_SERVER=3Dinternal-lkp-server
          nokaslr
          selinux=3D0
          debug
          apic=3Ddebug
          sysrq_always_enabled
          rcupdate.rcu_cpu_stall_timeout=3D100
          net.ifnames=3D0
          printk.devkmsg=3Don
          panic=3D-1
          softlockup_panic=3D1
          nmi_watchdog=3Dpanic
          oops=3Dpanic
          load_ramdisk=3D2
          prompt_ramdisk=3D0
          drbd.minor_count=3D8
          systemd.log_level=3Derr
          ignore_loglevel
          console=3Dtty0
          earlyprintk=3DttyS0,115200
          console=3DttyS0,115200
          vga=3Dnormal
          rw
          keep_initrds=3D/osimage/pkg/debian-13-x86_64-20250902.cgz/ltp-x86=
_64-ed2758122-1_20260711.cgz
          acpi_rsdp=3D0x000f0490
Machine:  unknown
Arch:     x86_64
RAM:      6895596 kB
Swap:     0 kB
Distro:   debian 13

=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=
=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=
=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80
      TEST SUMMARY
=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=
=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=
=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80
Suite:   syscalls-03
Runtime: 3m 24s
Runs:    183

Results:
    Passed:   2144
    Failed:   1
    Broken:   0
    Skipped:  222
    Warnings: 0

=1B[1;31mFailures:=1B[0m
    =E2=80=A2 ioctl03



The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20260715/202607151550.5d829a99-lkp@=
intel.com



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0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki