[LTP] stable-rc-5.3.9-rc1: regressions detected - remove_proc_entry: removing non-empty directory 'net/dev_snmp6', leaking at least 'lo'

[Naresh Kamboju]

Linux stable rc 5.3 branch running LTP reported following test failures.
While investigating these failures I have found this kernel warning
from boot console.
Please find detailed LTP output log in the bottom of this email.

List of regression test cases:
  ltp-containers-tests:
    * netns_breakns_ip_ipv6_ioctl
    * netns_breakns_ip_ipv6_netlink
    * netns_breakns_ns_exec_ipv6_ioctl
    * netns_breakns_ns_exec_ipv6_netlink
    * netns_comm_ip_ipv6_ioctl
    * netns_comm_ip_ipv6_netlink
    * netns_comm_ns_exec_ipv6_ioctl
    * netns_comm_ns_exec_ipv6_netlink

dmesg log:
[    0.000000] Linux version 5.3.9-rc1 (oe-user@oe-host) (gcc version
7.3.0 (GCC)) #1 SMP PREEMPT Mon Nov 4 12:14:24 UTC 2019
[    0.000000] Machine model: ARM Juno development board (r2)
...
[    3.670227] ------------[ cut here ]------------
[    3.674887] remove_proc_entry: removing non-empty directory
'net/dev_snmp6', leaking at least 'lo'
[    3.684183] WARNING: CPU: 1 PID: 1 at
/usr/src/kernel/fs/proc/generic.c:684 remove_proc_entry+0x194/0x1a8
[    3.693658] Modules linked in:
[    3.696687] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.3.9-rc1 #1
[    3.702806] Hardware name: ARM Juno development board (r2) (DT)
[    3.708669] pstate: 40000005 (nZcv daif -PAN -UAO)
[    3.713414] pc : remove_proc_entry+0x194/0x1a8
[    3.717814] lr : remove_proc_entry+0x194/0x1a8
[    3.722213] sp : ffff00001003bbe0
[    3.725494] x29: ffff00001003bbe0 x28: ffff0000119cddc0
[    3.730757] x27: ffff000012256000 x26: ffff00001220b000
[    3.736019] x25: ffff00001220a000 x24: ffff000012209000
[    3.741280] x23: ffff8009754a6b00 x22: ffff800973a536db
[    3.746541] x21: ffff800973a53600 x20: ffff000011f8f000
[    3.751803] x19: ffff8009754a6bdb x18: ffffffffffffffff
[    3.757065] x17: 0000000000000007 x16: 0000000000000000
[    3.762326] x15: ffff000011f8f848 x14: ffff80097396f108
[    3.767588] x13: ffff80097396f107 x12: ffff000012268b70
[    3.772849] x11: ffff000012268000 x10: 0000000000000028
[    3.778111] x9 : 0000000000000000 x8 : ffff000011f8f848
[    3.783372] x7 : 00000000b2722639 x6 : ffff000011f93000
[    3.788634] x5 : 0000000000000000 x4 : ffff800975dd8000
[    3.793895] x3 : ffff000011f90000 x2 : 0000000000000000
[    3.799157] x1 : 43129acc141cb700 x0 : 0000000000000000
[    3.804419] Call trace:
[    3.806841]  remove_proc_entry+0x194/0x1a8
[    3.810900]  ipv6_proc_exit_net+0x38/0x58
[    3.814872]  ops_exit_list.isra.1+0x54/0x88
[    3.819013]  unregister_pernet_operations+0xec/0x150
[    3.823929]  unregister_pernet_subsys+0x34/0x48
[    3.828416]  ipv6_misc_proc_exit+0x1c/0x28
[    3.832473]  inet6_init+0x2a4/0x33c
[    3.835929]  do_one_initcall+0x94/0x458
[    3.839727]  kernel_init_freeable+0x484/0x52c
[    3.844043]  kernel_init+0x18/0x110
[    3.847498]  ret_from_fork+0x10/0x1c
[    3.851037] irq event stamp: 255276
[    3.854492] hardirqs last  enabled at (255275):
[<ffff00001104f828>] _raw_spin_unlock_irq+0x38/0x78
[    3.863453] hardirqs last disabled at (255276):
[<ffff0000100a5a14>] debug_exception_enter+0xac/0xe8
[    3.872498] softirqs last  enabled at (255270):
[<ffff00001008210c>] __do_softirq+0x474/0x580
[    3.880943] softirqs last disabled at (255259):
[<ffff0000101018e4>] irq_exit+0x144/0x150
[    3.889044] ---[ end trace 6cbc85548f1f4bc5 ]---

...
LTP test trimmed output,

RTNETLINK answers: Operation not supported
netns_breakns_ns_exec_ipv6_netlink 1 TBROK: adding address to veth0 failed
tee: /proc/sys/net/ipv6/conf/veth0/accept_dad: No such file or directory
tee: /proc/sys/net/ipv6/conf/veth0/accept_ra: No such file or directory
tee: /proc/sys/net/ipv6/conf/veth1/accept_dad: No such file or directory
tee: /proc/sys/net/ipv6/conf/veth1/accept_ra: No such file or directory
No support for INET6 on this system.
netns_breakns_ns_exec_ipv6_ioctl 1 TBROK: adding address to veth0 failed
netns_breakns_ip_ipv6_netlink 1 TBROK: adding address to veth0 failed
netns_breakns_ip_ipv6_ioctl 1 TBROK: adding address to veth0 failed
netns_comm_ns_exec_ipv6_netlink 1 TBROK: adding address to veth0 failed
netns_comm_ns_exec_ipv6_ioctl 1 TBROK: adding address to veth0 failed
netns_comm_ip_ipv6_netlink 1 TBROK: adding address to veth0 failed
netns_comm_ip_ipv6_ioctl 1 TBROK: adding address to veth0 failed

metadata:
  git branch: linux-5.3.y
  git repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
  git commit: ff21af282725ae2ebc3ac4298513816f760c929e
  git describe: v5.3.8-160-gff21af282725
  make_kernelversion: 5.3.9-rc1
  kernel-config:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/juno/lkft/linux-stable-rc-5.3/35/config
  kernel-defconfig:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/juno/lkft/linux-stable-rc-5.3/35/defconfig
  build-url: https://ci.linaro.org/job/openembedded-lkft-linux-stable-rc-5.3/DISTRO=lkft,MACHINE=juno,label=docker-lkft/35/
  build-location:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/juno/lkft/linux-stable-rc-5.3/35

We are investigating this problem.

Full test logs,
https://qa-reports.linaro.org/lkft/linux-stable-rc-5.3-oe/build/v5.3.8-160-gff21af282725/testrun/991864/log
https://qa-reports.linaro.org/lkft/linux-stable-rc-5.3-oe/build/v5.3.8-160-gff21af282725/testrun/991901/log
https://qa-reports.linaro.org/lkft/linux-stable-rc-5.3-oe/build/v5.3.8-160-gff21af282725/testrun/991922/log
https://qa-reports.linaro.org/lkft/linux-stable-rc-5.3-oe/build/v5.3.8-160-gff21af282725/testrun/991884/log
https://qa-reports.linaro.org/lkft/linux-stable-rc-5.3-oe/build/v5.3.8-160-gff21af282725/testrun/991846/log

--
Linaro LKFT
https://lkft.linaro.org/