It took a while, but v4.15-rc6 fails; so we need to move back a bit.


[ 2541.139904] bcache: bcache_device_free() bcache0 stopped
[ 2541.141848] BUG: unable to handle kernel NULL pointer dereference
at 0000000000000d38
[ 2541.143813] IP: search_free+0ex01-b6435-e1/5f0x40 [bcache]
[ 2541.145676] PGD 0 P4D 0
[ 2541.146493] Oops: 0000 [#58] SMP
[ 2541.147509] Modules linked in: bcache nls_utf8 isofs nls_iso8859_1
ppdev kvm_intel kvm irqbypass joydev input_leds parport_pc parport
mac_hid serio_raw sch_fq_codel ib_iser rdma_cm iw_cm ib_cm ib_core
iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi virtio_rng
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 psmouse virtio_net
virtio_scsi virtio_blk i2c_piix4 pata_acpi floppy
[ 2541.154248] CPU: 3 PID: 13332 Comm: kworker/3:200 Tainted: G      D
         4.15.0-041500rc6-generic #201712312330
[ 2541.156921] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 2541.159381] Workqueue: bcache bch_data_insert_keys [bcache]
[ 2541.160566] RIP: 0010:search_free+0x31/0x40 [bcache]
[ 2541.161300] RSP: 0018:ffffb04e45b6bdf8 EFLAGS: 00010282
[ 2541.162098] RAX: 0000000000000000 RBX: ffff942c22b3b390 RCX: 0000000180100006
[ 2541.163791] RDX: 0000000180100007 RSI: ffffded4c086a7c0 RDI: ffff942c22b3b390
[ 2541.165486] RBP: ffffb04e45b6be00 R08: ffff942c21a9fc00 R09: 0000000180100006
[ 2541.167191] R10: ffffb04e45b6bd70 R11: ffff942c3ffb4000 R12: ffff942c39610010
[ 2541.168897] R13: ffff942c22b3b518 R14: ffff942c3fda3080 R15: ffff942c26b526c0
[ 2541.170637] FS:  0000000000000000(0000) GS:ffff942c3fd80000(0000)
knlGS:0000000000000000
[ 2541.172574] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2541.174043] CR2: 0000000000000d38 CR3: 0000000011409000 CR4: 00000000000006e0
[ 2541.175847] Call Trace:
[ 2541.176349]  cached_dev_cache_miss_done+0x38/0x80 [bcache]
[ 2541.177131]  closure_put+0x8b/0xc0 [bcache]
[ 2541.177791]  closure_sub+0x6f/0xc0 [bcache]
[ 2541.178924]  bch_data_insert_keys+0xd8/0x130 [bcache]
[ 2541.180107]  process_one_work+0x1ea/0x410
[ 2541.181176]  worker_thread+0x32/0x410
[ 2541.182157]  kthread+0x11e/0x140
[ 2541.183043]  ? process_one_work+0x410/0x410
[ 2541.184154]  ? kthread_create_worker_on_cpu+0x70/0x70
[ 2541.185460]  ret_from_fork+0x1f/0x30
[ 2541.186397] Code: 48 89 e5 53 48 89 fb e8 0e ff ff ff 48 8b bb 68
01 00 00 48 85 ff 74 05 e8 cd 0b d0 f5 48 8b 83 e8 00 00 00 48 89 df
48 8b 40 70 <48> 8b b0 38 0d 00 00 e8 c3 18 a9 f5 5b 5d c3 0f 1f 44 00
00 55
[ 2541.189920] RIP: search_free+0x31/0x40 [bcache] RSP: ffffb04e45b6bdf8
[ 2541.191636] CR2: 0000000000000d38
[ 2541.192503] ---[ end trace e2b7818e7472ac25 ]---
On Mon, Nov 26, 2018 at 8:26 PM Joseph Salisbury
<email address hidden> wrote:

>
> Can you confirm that v4.15-rc6 does not exhibit the bug?  That will
> ensure I'm reviewing the correct commits:
>
> http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.15-rc6/
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1784665
>
> Title:
>   mkfs.ext4 over /dev/bcache0 hangs
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1784665/+subscriptions