block_dev from kernel_misc test suite in LTP generates kernel traces

[Po-Hsu Lin]

The test will pass, but there will be some kernel trace messages in the syslog:

 ltp_block_dev: Test Case 7: unregister_blkdev() with major=0
 WARNING: CPU: 0 PID: 13195 at block/genhd.c:415 unregister_blkdev+0x64/0xb0
 Modules linked in: ltp_block_dev(OE) msdos minix nls_iso8859_1 xfs binfmt_misc cfg80211 kvm_intel kvm irqbypass input_leds joydev serio_raw mac_hid sch_fq_codel ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables x_tables autofs4 btrfs zstd_compress raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear cirrus ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops floppy drm psmouse virtio_blk virtio_net net_failover i2c_piix4 failover pata_acpi [last unloaded: zram]
 CPU: 0 PID: 13195 Comm: block_dev Tainted: P W OE 4.18.0-20-generic #21-Ubuntu
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
 RIP: 0010:unregister_blkdev+0x64/0xb0
 Code: 00 48 63 c3 48 8b 04 c5 40 83 12 ad 48 85 c0 74 19 44 3b 60 08 75 0b eb 4c 44 39 63 08 74 2a 48 89 d8 48 8b 18 48 85 db 75 ef <0f> 0b 31 db 48 c7 c7 00 90 b7 ac e8 7c 88 55 00 48 89 df e8 f4 13
 RSP: 0018:ffffbc89c0c8fdc0 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
 RDX: ffff9cf134f7d700 RSI: ffffffffc09a4805 RDI: ffffffffacb79000
 RBP: ffffbc89c0c8fdd8 R08: ffff9cf13fc27080 R09: 000000000000142f
 R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000000
 R13: ffffffffc09a4805 R14: ffffbc89c0c8fee8 R15: fffffffffffffff2
 FS: 00007fa58aa0d5c0(0000) GS:ffff9cf13fc00000(0000) knlGS:0000000000000000
 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000556033aef4c8 CR3: 0000000074b1e000 CR4: 00000000000006f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  sys_tcase.cold.0+0x1e8/0x77b [ltp_block_dev]
  dev_attr_store+0x1b/0x30
  sysfs_kf_write+0x3b/0x50
  kernfs_fop_write+0x12e/0x1b0
  __vfs_write+0x1b/0x40
  vfs_write+0xab/0x1b0
  ksys_write+0x55/0xc0
  __x64_sys_write+0x1a/0x20
  do_syscall_64+0x5a/0x110
  entry_SYSCALL_64_after_hwframe+0x44/0xa9
 RIP: 0033:0x7fa58a92bfd4
 Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 48 8d 05 29 f7 0d 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 49 89 d4 55 48 89 f5 53
 RSP: 002b:00007fff0cd747c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fa58a92bfd4
 RDX: 0000000000000001 RSI: 0000556033aee4c0 RDI: 0000000000000015
 RBP: 0000556033aee4c0 R08: 00007fa58aa0d5c0 R09: 0000000000000000
 R10: 0000556032d004f6 R11: 0000000000000246 R12: 0000556033aed280
 R13: 0000000000000001 R14: 00007fa58aa032a0 R15: 00007fa58aa02760
 ---[ end trace 7d89482f2331d988 ]---

 0 test cases failed
 startup='Wed May 22 07:57:20 2019'
 block_dev 1 TPASS : Test-case '1'
 block_dev 2 TPASS : Test-case '2'
 block_dev 3 TPASS : Test-case '3'
 block_dev 4 TPASS : Test-case '4'
 block_dev 5 TPASS : Test-case '5'
 block_dev 6 TPASS : Test-case '6'
 block_dev 7 TPASS : Test-case '7'
 tag=block_dev stime=1558511840 dur=0 exit=exited stat=0 core=no cu=0 cs=0

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: linux-image-4.18.0-20-generic 4.18.0-20.21
ProcVersionSignature: User Name 4.18.0-20.21-generic 4.18.20
Uname: Linux 4.18.0-20-generic x86_64
AlsaDevices:
 total 0
 crw-rw---- 1 root audio 116, 1 May 22 06:28 seq
 crw-rw---- 1 root audio 116, 33 May 22 06:28 timer
AplayDevices: Error: [Errno 2] No such file or directory: 'aplay': 'aplay'
ApportVersion: 2.20.10-0ubuntu13.3
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord': 'arecord'
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
CurrentDmesg:

Date: Wed May 22 07:57:40 2019
IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig': 'iwconfig'
Lsusb: Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: QEMU Standard PC (i440FX + PIIX, 1996)
PciMultimedia:

ProcFB: 0 cirrusdrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.18.0-20-generic root=UUID=2a4b0342-a2dd-4feb-b3e2-9644ca1c4a60 ro
RelatedPackageVersions:
 linux-restricted-modules-4.18.0-20-generic N/A
 linux-backports-modules-4.18.0-20-generic N/A
 linux-firmware 1.175.4
RfKill: Error: [Errno 2] No such file or directory: 'rfkill': 'rfkill'
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/01/2014
dmi.bios.vendor: SeaBIOS
dmi.bios.version: Ubuntu-1.8.2-1ubuntu1
dmi.chassis.type: 1
dmi.chassis.vendor: QEMU
dmi.chassis.version: pc-i440fx-xenial
dmi.modalias: dmi:bvnSeaBIOS:bvrUbuntu-1.8.2-1ubuntu1:bd04/01/2014:svnQEMU:pnStandardPC(i440FX+PIIX,1996):pvrpc-i440fx-xenial:cvnQEMU:ct1:cvrpc-i440fx-xenial:
dmi.product.name: Standard PC (i440FX + PIIX, 1996)
dmi.product.version: pc-i440fx-xenial
dmi.sys.vendor: QEMU

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1829994

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Po-Hsu Lin (cypressyew)]

It looks like this is an expected behaviour:

"Looking at the test and at the kernel source the test is triggering
exactly the condition it's supposed to to trigger and the warning is to
be expected.", comment from Cyril.

http://lists.linux.it/pipermail/ltp/2019-June/012255.html