Ubuntu
linux-lts-xenial package

ubuntu_zram_smoke_test failed on ppc64el with Trusty 4.4

Bug #1798291 reported by Po-Hsu Lin
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
ubuntu-kernel-tests
Fix Released
Undecided
Colin Ian King
linux-lts-xenial (Ubuntu)
Invalid
Low
Unassigned

Bug Description

We have two ppc64el node, but this issue was spotted on node "modoc" only.

Running '/home/ubuntu/autotest/client/tests/ubuntu_zram_smoke_test/ubuntu_zram_smoke_test.sh'
 PASSED: zram module loaded
 PASSED: got 1 compression streams
 PASSED: got lzo lz4 compression algorithmns
 /home/ubuntu/autotest/client/tests/ubuntu_zram_smoke_test/ubuntu_zram_smoke_test.sh: line 104: echo: write error: Device or resource busy
 Total of 128768 MB free memory
 Making zram disk of 42922 MB
 PASSED: mkfs.ext4 on ZRAM successful
 PASSED: ext4 on ZRAM (lzo), memory used: 2812464573 2776821624, file size: 2682 MB
 /home/ubuntu/autotest/client/tests/ubuntu_zram_smoke_test/ubuntu_zram_smoke_test.sh: line 104: echo: write error: Device or resource busy
 /home/ubuntu/autotest/client/tests/ubuntu_zram_smoke_test/ubuntu_zram_smoke_test.sh: line 110: echo: write error: Device or resource busy
 Total of 126144 MB free memory
 Making zram disk of 42048 MB
 /home/ubuntu/autotest/client/tests/ubuntu_zram_smoke_test/ubuntu_zram_smoke_test.sh: line 132: echo: write error: Device or resource busy
 PASSED: mkfs.ext4 on ZRAM successful
 PASSED: ext4 on ZRAM (lz4), memory used: 2755831009 2642592075, file size: 2628 MB
 modprobe: FATAL: Module zram is in use.
 FAILED: cannot unload zram module

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-4.4.0-137-generic 4.4.0-137.163~14.04.1
ProcVersionSignature: User Name 4.4.0-137.163~14.04.1-generic 4.4.144
Uname: Linux 4.4.0-137-generic ppc64le
ApportVersion: 2.14.1-0ubuntu3.29
Architecture: ppc64el
Date: Wed Oct 17 07:58:47 2018
ProcLoadAvg: 0.29 0.55 0.35 1/1189 5285
ProcLocks:
 1: FLOCK ADVISORY WRITE 3215 00:13:541 0 EOF
 2: POSIX ADVISORY WRITE 3256 00:13:544 0 EOF
 3: POSIX ADVISORY WRITE 3294 00:13:546 0 EOF
 4: POSIX ADVISORY WRITE 3149 00:13:519 0 EOF
ProcSwaps:
 Filename Type Size Used Priority
 /swap.img file 8388544 0 -1
ProcVersion: Linux version 4.4.0-137-generic (buildd@bos02-ppc64el-001) (gcc version 4.8.4 (User Name 4.8.4-2ubuntu1~14.04.4) ) #163~14.04.1-User Name SMP Mon Sep 24 17:14:22 UTC 2018
SourcePackage: linux-lts-xenial
UpgradeStatus: No upgrade log present (probably fresh install)
cpu_cores: Number of cores present = 20
cpu_coreson: Number of cores online = 20
cpu_smt: SMT=8

Revision history for this message
Po-Hsu Lin (cypressyew) wrote :
Revision history for this message
Po-Hsu Lin (cypressyew) wrote :

When inserting the zram module, it will be used by the lz4_compress module, and cannot be removed afterward:

ubuntu@modoc:~$ lsmod | grep zram
ubuntu@modoc:~$ sudo modprobe zram
ubuntu@modoc:~$ lsmod | grep zram
zram 33608 1
lz4_compress 4465 1 zram
ubuntu@modoc:~$ sudo modprobe -r zram
modprobe: FATAL: Module zram is in use.
ubuntu@modoc:~$ sudo modprobe -r lz4_compress
modprobe: FATAL: Module lz4_compress is in use.

Revision history for this message
Colin Ian King (colin-king) wrote :

That's unfortunate. Perhaps we should overlook the module removal part of the test for now.

Revision history for this message
Po-Hsu Lin (cypressyew) wrote :

OK for me,

but for the "Device or resource busy", it's caused by the ubuntu_zram_smoke_test.sh when trying to echo 1 to the reset, not sure if this is related.

(And not sure why this is only happening on one of the P8 node)

Revision history for this message
Colin Ian King (colin-king) wrote :

OK, We should look into that "Device or resource busy" error for sure. I wonder if that's because of a race on the device becoming online or something like that. If I can get access to the machine I will take a look.

Revision history for this message
Colin Ian King (colin-king) wrote :

After adding some debug I see that multipath is opening the device, hence bd_openers > 0 and we get the EBUSY return. Killing multipath fixes this. It also explains why we can't remove the module at the end of the test.

Changed in linux-lts-xenial (Ubuntu):
importance: Undecided → Low
status: New → In Progress
assignee: nobody → Colin Ian King (colin-king)
Revision history for this message
Po-Hsu Lin (cypressyew) wrote :

http://kernel.ubuntu.com/git/ubuntu/autotest-client-tests.git/commit/?id=83cc5bc390f37c3012330aa8c045205ec2347c1c

Changed in ubuntu-kernel-tests:
status: New → Fix Released
assignee: nobody → Colin Ian King (colin-king)
Po-Hsu Lin (cypressyew)
Changed in linux-lts-xenial (Ubuntu):
status: In Progress → Invalid
assignee: Colin Ian King (colin-king) → nobody
Revision history for this message
Colin Ian King (colin-king) wrote :

Thanks for testing this.

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