artful bcache NULL pointer defererence

[Ryan Harper]

[ 20.935396] BUG: unable to handle kernel NULL pointer dereference at 0000000000000b84
[ 20.936130] IP: _raw_spin_lock_irqsave+0x22/0x40
[ 20.936540] PGD 0
[ 20.936540] P4D 0
[ 20.936725]
[ 20.937117] Oops: 0002 [#1] SMP
[ 20.937570] Modules linked in: bcache psmouse virtio_blk virtio_net virtio_scsi pata_acpi floppy
[ 20.937686] bcache: bch_journal_replay() journal replay done, 558 keys in 30 entries, seq 593
[ 20.937782] bcache: register_cache() registered cache device vdc
[ 20.940029] CPU: 0 PID: 176 Comm: bcache_allocato Not tainted 4.13.0-19-generic #22-Ubuntu
[ 20.940825] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 20.942112] task: ffff95c0ef878000 task.stack: ffffa8f1c0394000
[ 20.942903] RIP: 0010:_raw_spin_lock_irqsave+0x22/0x40
[ 20.943606] RSP: 0018:ffffa8f1c0397d00 EFLAGS: 00010046
[ 20.944232] RAX: 0000000000000000 RBX: 0000000000000246 RCX: 0000000000000000
[ 20.944849] RDX: 0000000000000001 RSI: 0000000000000003 RDI: 0000000000000b84
[ 20.945503] RBP: ffffa8f1c0397d08 R08: ffffffffc0376a20 R09: aaaaaaaaaaaaaaab
[ 20.946125] R10: ffffa8f1c0369000 R11: ffff95c0fd120e78 R12: 0000000000000b84
[ 20.946745] R13: 0000000000000000 R14: 0000000000000021 R15: 0000000000000000
[ 20.947366] FS: 0000000000000000(0000) GS:ffff95c0ffc00000(0000) knlGS:0000000000000000
[ 20.948112] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 20.948124] bcache: register_bdev() registered backing device vda2
[ 20.949494] CR2: 0000000000000b84 CR3: 000000002fb8e000 CR4: 00000000000006f0
[ 20.950311] Call Trace:
[ 20.950607] try_to_wake_up+0x40/0x480
[ 20.951048] wake_up_process+0x15/0x20
[ 20.951490] bch_bucket_alloc+0xa5/0x320 [bcache]
[ 20.952043] ? wait_woken+0x80/0x80
[ 20.952387] bch_prio_write+0x19f/0x340 [bcache]
[ 20.952797] bch_allocator_thread+0x569/0xc80 [bcache]
[ 20.953546] kthread+0x125/0x140
[ 20.953869] ? bch_invalidate_one_bucket+0x80/0x80 [bcache]
[ 20.954363] ? kthread_create_on_node+0x70/0x70
[ 20.954764] ret_from_fork+0x25/0x30
[ 20.955083] Code: ff 66 90 5d c3 0f 1f 40 00 0f 1f 44 00 00 55 48 89 e5 53 9c 58 0f 1f 44 00 00 48 89 c3 fa 66 0f 1f 44 00 00 31 c0 ba 01 00 00 00 <f0> 0f b1 17 85 c0 75 06 48 89 d8 5b 5d c3 89 c6 e8 19 63 7c ff
[ 20.956770] RIP: _raw_spin_lock_irqsave+0x22/0x40 RSP: ffffa8f1c0397d00
[ 20.957579] CR2: 0000000000000b84
[ 20.958038] ---[ end trace 2fbf49a9fcc4299e ]---
[ 21.088078] tsc: Refined TSC clocksource calibration: 2397.221 MHz
[ 21.089038] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x228df650ba8, max_idle_ns: 440795214877 ns
Begin: Loading essential drivers ... [ 203.088012] raid6: sse2x1 gen() 5302 MB/s

Launched a vm like this:

 qemu-system-x86_64 -enable-kvm \
  -device virtio-scsi-pci,id=virtio-scsi-xkvm \
  -device virtio-net-pci,netdev=net00 -netdev type=user,id=net00 \
  -drive file=/var/lib/jenkins/slaves/torkoal/workspace/curtin-vmtest-devel-amd64/output/ArtfulBcacheBasic/disks/install_disk.img,id=disk00,if=none,format=raw,index=0 \
  -device virtio-blk,drive=disk00,serial=install_disk.img,logical_block_size=512,physical_block_size=512,min_io_size=512 \
  -drive file=/var/lib/jenkins/slaves/torkoal/workspace/curtin-vmtest-devel-amd64/output/ArtfulBcacheBasic/boot/output_disk.img,id=disk01,if=none,format=raw,index=1 \
  -device virtio-blk,drive=disk01,serial=output_disk.img,logical_block_size=512,physical_block_size=512,min_io_size=512 \
  -drive file=/var/lib/jenkins/slaves/torkoal/workspace/curtin-vmtest-devel-amd64/output/ArtfulBcacheBasic/disks/extra_disk_0.img,id=disk02,if=none,format=raw,index=2 \
  -device virtio-blk,drive=disk02,serial=extra_disk_0.img,logical_block_size=512,physical_block_size=512,min_io_size=512 \
  -drive file=/var/lib/jenkins/slaves/torkoal/workspace/curtin-vmtest-devel-amd64/output/ArtfulBcacheBasic/boot/seed.img,id=disk03,if=none,format=raw,index=3,media=cdrom -device virtio-blk,drive=disk03,serial=seed.img -smp 2 -m 1024 -nographic -serial file:/var/lib/jenkins/slaves/torkoal/workspace/curtin-vmtest-devel-amd64/output/ArtfulBcacheBasic/logs/boot-serial.log

[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 1737817

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.

[Joseph Salisbury (jsalisbury)]

Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.15 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.15-rc3

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]