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

Wed Jul 15 16:01:46 CEST 2026

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/20260709-181234
base: https://git.kernel.org/cgit/linux/kernel/git/davem/net.git fabb881df322da25442f98d23f5fa371e3c78ec4
patch link: https://lore.kernel.org/all/20260709095511.168235-1-simon.schippers@tu-dortmund.de/
patch subject: [PATCH net v3] tun/tap & vhost-net: make qdisc backpressure opt-in via IFF_BACKPRESSURE

in testcase: ltp
version: 
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 version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202607151550.5d829a99-lkp@intel.com

....

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

....

Execution time: 3m 35s

Disconnecting from SUT: default

Target information
──────────────────
Kernel:   Linux 7.2.0-rc1+ #1 SMP PREEMPT_DYNAMIC Sun Jul 12 07:25:38 CST 2026
Cmdline:  ip=::::lkp-ivb-d04::dhcp
          root=/dev/ram0
          RESULT_ROOT=/result/ltp/1HDD-ext4-syscalls-03/lkp-ivb-d04/debian-13-x86_64-20250902.cgz/x86_64-rhel-9.4-ltp/gcc-14/09154ff2072e36b86ba2d92d436b7f27df153ed1/0
          BOOT_IMAGE=/pkg/linux/x86_64-rhel-9.4-ltp/gcc-14/09154ff2072e36b86ba2d92d436b7f27df153ed1/vmlinuz-7.2.0-rc1+
          branch=linux-devel/devel-hourly-20260709-190759
          job=/lkp/jobs/scheduled/lkp-ivb-d04/ltp-1HDD-ext4-syscalls-03-debian-13-x86_64-20250902.cgz-09154ff2072e-20260712-19649-tc8bu6-0.yaml
          user=lkp
          ARCH=x86_64
          kconfig=x86_64-rhel-9.4-ltp
          commit=09154ff2072e36b86ba2d92d436b7f27df153ed1
          intremap=posted_msi
          max_uptime=7200
          LKP_SERVER=internal-lkp-server
          nokaslr
          selinux=0
          debug
          apic=debug
          sysrq_always_enabled
          rcupdate.rcu_cpu_stall_timeout=100
          net.ifnames=0
          printk.devkmsg=on
          panic=-1
          softlockup_panic=1
          nmi_watchdog=panic
          oops=panic
          load_ramdisk=2
          prompt_ramdisk=0
          drbd.minor_count=8
          systemd.log_level=err
          ignore_loglevel
          console=tty0
          earlyprintk=ttyS0,115200
          console=ttyS0,115200
          vga=normal
          rw
          keep_initrds=/osimage/pkg/debian-13-x86_64-20250902.cgz/ltp-x86_64-ed2758122-1_20260711.cgz
          acpi_rsdp=0x000f0490
Machine:  unknown
Arch:     x86_64
RAM:      6895596 kB
Swap:     0 kB
Distro:   debian 13

────────────────────────
      TEST SUMMARY
────────────────────────
Suite:   syscalls-03
Runtime: 3m 24s
Runs:    183

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

[1;31mFailures:[0m
    • ioctl03

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

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