Hey, Po-Hsu Lin. I marked this as a duplicate of #1999554, as I did some research on it before. So, many of these tests use a loop device and then try to clear it. The clear function will retry multiple times because udev may have a hold on the device. After a number of tries with some timeout, it will emit that WARNING because the loop device failed to clear. That is because udev still has a hold on it.
I debugged this and the reason for that is because udev will read efivars every once in a while (instead of caching the results), and reading efivar on those gcp instance types takes multiple seconds. That has been causing other issues, like nbd being busy as well and that test failing. I believe this should be fixed on udev. Cascardo. ** Also affects: udev (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1999554 Title: LTP uevent01 will fail on GCP n2d-standard-64 Status in linux package in Ubuntu: Confirmed Status in udev package in Ubuntu: New Bug description: Because udev takes too long to release the loop device, LTP test uevent01 (and some other tests) may warn about not being able to detach the loop device. This is identified as a failure. ubuntu@selfprovisioned-cascardo-n2d:~$ sudo ./uevent01 tst_test.c:1423: TINFO: Timeout per run is 0h 05m 00s tst_device.c:88: TINFO: Found free device 6 '/dev/loop6' uevent01.c:24: TINFO: Attaching device /dev/loop6 uevent.h:49: TINFO: Got uevent: uevent.h:52: TINFO: change@/devices/virtual/block/loop6 uevent.h:52: TINFO: ACTION=change uevent.h:52: TINFO: DEVPATH=/devices/virtual/block/loop6 uevent.h:52: TINFO: SUBSYSTEM=block uevent.h:52: TINFO: DISK_MEDIA_CHANGE=1 uevent.h:52: TINFO: MAJOR=7 uevent.h:52: TINFO: MINOR=6 uevent.h:52: TINFO: DEVNAME=loop6 uevent.h:52: TINFO: DEVTYPE=disk uevent.h:52: TINFO: DISKSEQ=7 uevent.h:52: TINFO: SEQNUM=2959 uevent.h:140: TPASS: Got expected UEVENT uevent.h:49: TINFO: Got uevent: uevent.h:52: TINFO: change@/devices/virtual/block/loop6 uevent.h:52: TINFO: ACTION=change uevent.h:52: TINFO: DEVPATH=/devices/virtual/block/loop6 uevent.h:52: TINFO: SUBSYSTEM=block uevent.h:52: TINFO: MAJOR=7 uevent.h:52: TINFO: MINOR=6 uevent.h:52: TINFO: DEVNAME=loop6 uevent.h:52: TINFO: DEVTYPE=disk uevent.h:52: TINFO: DISKSEQ=7 uevent.h:52: TINFO: SEQNUM=2960 uevent.h:140: TPASS: Got expected UEVENT uevent01.c:26: TINFO: Detaching device /dev/loop6 tst_device.c:254: TWARN: ioctl(/dev/loop6, LOOP_CLR_FD, 0) no ENXIO for too long Summary: passed 2 failed 0 broken 0 skipped 0 warnings 1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1999554/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp