Hi, all!
After running tools/testing/selftests/net/tun, there seems to be some kind of hang in test "FAIL tun.reattach_delete_close" or "FAIL tun.reattach_close_delete".
Two tests exit by timeout, but the processes left are unkillable, even with kill -9 PID:
[root@pc-mtodorov linux_torvalds]# ps -ef | grep tun root 1140 1 0 12:16 ? 00:00:00 /bin/bash /usr/sbin/ksmtuned root 1333 1 0 12:16 ? 00:00:01 /usr/libexec/platform-python -Es /usr/sbin/tuned -l -P root 3930 2309 0 12:20 pts/1 00:00:00 tools/testing/selftests/net/tun root 3952 2309 0 12:21 pts/1 00:00:00 tools/testing/selftests/net/tun root 4056 3765 0 12:25 pts/1 00:00:00 grep --color=auto tun [root@pc-mtodorov linux_torvalds]# kill -9 3930 3952 [root@pc-mtodorov linux_torvalds]# ps -ef | grep tun root 1140 1 0 12:16 ? 00:00:00 /bin/bash /usr/sbin/ksmtuned root 1333 1 0 12:16 ? 00:00:01 /usr/libexec/platform-python -Es /usr/sbin/tuned -l -P root 3930 2309 0 12:20 pts/1 00:00:00 tools/testing/selftests/net/tun root 3952 2309 0 12:21 pts/1 00:00:00 tools/testing/selftests/net/tun root 4060 3765 0 12:25 pts/1 00:00:00 grep --color=auto tun [root@pc-mtodorov linux_torvalds]#
The kernel seems to be stuck in some loop, and filling the log with the following messages until reboot, where it is also waiting very long on the situation to timeout, which apparently never happens.
Mar 14 11:54:09 pc-mtodorov kernel: unregister_netdevice: waiting for tap0 to become free. Usage count = 3 Mar 14 11:54:19 pc-mtodorov kernel: unregister_netdevice: waiting for tap0 to become free. Usage count = 3 Mar 14 11:54:29 pc-mtodorov kernel: unregister_netdevice: waiting for tap0 to become free. Usage count = 3 Mar 14 11:54:40 pc-mtodorov kernel: unregister_netdevice: waiting for tap0 to become free. Usage count = 3 Mar 14 11:54:50 pc-mtodorov kernel: unregister_netdevice: waiting for tap0 to become free. Usage count = 3
The platform is kernel 6.3.0-rc2 on AlmaLinux 8.7 and a LENOVO_MT_10TX_BU_Lenovo_FM_V530S-07ICB (lshw output attached).
The .config is here:
https://domac.alu.hr/~mtodorov/linux/selftests/net-tun/config-6.3.0-rc2-mg-a...
Basically, it is a vanilla Torvalds tree kernel with MGLRU, KMEMLEAK, and CONFIG_DEBUG_KOBJECT enabled. And devres patch.
Please find the strace of the net/tun run attached.
I am available for additional diagnostics.
Hope this helps.
Best regards, Mirsad