Re: [gentoo-user] Warnings on shutting down bcache: WARNING: CPU: 1 PID: 4378 at lib/idr.c:383

[Andrew Savchenko]

On Tue, 15 Aug 2017 14:07:42 +0200 Håkon Alstadheim wrote:
> I'm getting some noise in my logs when shutting down bcache.
> My system:
> Linux gentoo 4.12.7-gentoo #1 SMP Sun Aug 13 22:56:20 CEST 2017 x86_64
> Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz GenuineIntel GNU/Linux
> Running as dom0 under Xen-4.9.0
>
> My shutdown script loops over the bcache devices like so:
> ---
> for f in /sys/fs/bcache/854fc80e-5499-413f-b90b-87a803eaca7e/bdev*; do
>     bdev=$(basename $f )
>     if [ -e $f/stop ]; then
> 	logger -t "init.d/probe-home-partition" -p daemon.warning\
> "Stopping $bdev"
> 	einfo "Stopping $bdev"
> 	if ! echo 1 > $f/stop ; then
> 	  ewarn "Could not stop $bdev"
> 	  logger -t "init.d/probe-home-partition" -p daemon.warning\
>  "Could not stop $bdev"
> 	fi
> 	usleep 300
> 	sleep 1
>     else
> 	einfo "$bdev not cached?"
> 	logger -t "init.d/probe-home-partition" -p daemon.warning \
> "$bdev not cached ?"
>     fi
> done
>
> -----
> This gives me in daemon.log:
> -----
> Aug 14 09:31:21 gentoo init.d/probe-home-partition: Stopping bdev15
> Aug 14 09:31:22 gentoo init.d/probe-home-partition: Stopping bdev16
> Aug 14 09:31:23 gentoo init.d/probe-home-partition: Stopping bdev17
> Aug 14 09:31:24 gentoo init.d/probe-home-partition: Stopping bdev18
> Aug 14 09:31:25 gentoo init.d/probe-home-partition: Stopping bdev19
> Aug 14 09:31:26 gentoo init.d/probe-home-partition: Stopping cache set
> -----
> But it seems bcache is doing something weird, stopping a device called
> bcache0, which I do not have, before stopping the first of my bcache
> devices. ALL runs of "echo 1 > $device/stop" provoke a warning in
> lib/idr.c on that same line. It may be that my stopping of the bcache
> devices is wrong, un-necessary and misguided, but it should still work
> the way I am doing it, should it not?
>
>
> ---kern.log:---
> ...
> [140395.421994] nfsd: last server has exited, flushing export cache
> [140397.011932] XFS (bcache16): Unmounting Filesystem
> [140397.248911] bcache: bcache_device_free() bcache0 stopped
> [140398.300187] bcache: bcache_device_free() bcache16 stopped
> [140398.381951] ida_remove called for id=16 which is not allocated.
> [140398.381975] ------------[ cut here ]------------
> [140398.381985] WARNING: CPU: 1 PID: 4378 at lib/idr.c:383
> ida_remove+0xde/0xef
> [140398.381987] Modules linked in: xt_physdev iptable_filter ip_tables
> x_tables nfsd auth_rpcgss oid_registry nfsv4 dns_resolver nfsv3 nfs_acl
> iTCO_wdt iTCO_vendor_support binfmt_misc tun usbip_host usbip_core
> pktcdvd xen_wdt xen_blkback intel_rapl amdgpu intel_powerclamp
> crc32c_intel serio_raw drm_kms_helper pcspkr syscopyarea sysfillrect
> sysimgblt fb_sys_fops ttm lpc_ich i2c_i801 snd_hda_codec_realtek drm
> snd_hda_codec_generic bcache snd_usb_audio snd_usbmidi_lib snd_hda_intel
> snd_rawmidi snd_hda_codec snd_seq_device snd_hwdep snd_hda_core snd_pcm
> snd_timer snd cp210x usbserial nct6775 input_leds hwmon_vid shpchp
> ipmi_ssif wmi acpi_power_meter dm_zero dm_thin_pool dm_persistent_data
> dm_bio_prison dm_service_time dm_round_robin dm_queue_length
> dm_multipath dm_log_userspace cn virtio_pci virtio_scsi
> [140398.382056]  virtio_blk virtio_console virtio_balloon xts aes_x86_64
> cbc sha512_generic sha1_generic libiscsi scsi_transport_iscsi macvlan
> virtio_net virtio_ring virtio e1000 fuse overlay nfs lockd grace sunrpc
> fscache jfs multipath linear raid10 raid1 raid0 dm_raid raid456
> async_raid6_recov async_memcpy async_pq async_xor xor async_tx raid6_pq
> dm_snapshot dm_bufio dm_crypt dm_mirror dm_region_hash dm_log dm_mod dax
> hid_sunplus hid_sony hid_samsung hid_pl hid_petalynx hid_monterey
> hid_microsoft hid_logitech ff_memless hid_gyration hid_ezkey hid_cypress
> hid_chicony hid_cherry hid_a4tech sl811_hcd xhci_plat_hcd ohci_pci
> ohci_hcd uhci_hcd aic94xx lpfc qla2xxx aacraid sx8 DAC960 hpsa cciss
> 3w_9xxx 3w_xxxx mptsas mptfc scsi_transport_fc mptspi mptscsih mptbase
> atp870u dc395x qla1280 imm parport dmx3191d
> [140398.382139]  sym53c8xx gdth initio BusLogic arcmsr aic7xxx aic79xx
> sg pdc_adma sata_inic162x sata_mv sata_qstor sata_vsc sata_uli sata_sis
> sata_sx4 sata_nv sata_via sata_svw sata_sil24 sata_sil sata_promise
> pata_sis usbhid led_class igb ptp dca i2c_algo_bit ehci_pci ehci_hcd
> xhci_pci megaraid_sas xhci_hcd
> [140398.382175] CPU: 1 PID: 4378 Comm: kworker/1:2 Not tainted
> 4.12.6-gentoo #1
> [140398.382177] Hardware name: ASUSTeK COMPUTER INC. Z10PE-D8
> WS/Z10PE-D8 WS, BIOS 3407 03/10/2017
> [140398.382190] Workqueue: events cached_dev_free [bcache]
> [140398.382193] task: ffff880216b24240 task.stack: ffffc900431e4000
> [140398.382197] RIP: e030:ida_remove+0xde/0xef
> [140398.382199] RSP: e02b:ffffc900431e7db0 EFLAGS: 00010082
> [140398.382202] RAX: 0000000000000033 RBX: 0000000000000012 RCX:
> 0000000000000000
> [140398.382204] RDX: ffff880249654450 RSI: ffff88024964dc08 RDI:
> ffff88024964dc08
> [140398.382205] RBP: ffffc900431e7e10 R08: 0000000000000000 R09:
> 00000000000448da
> [140398.382207] R10: 0000000000001668 R11: ffffffff81f1dad0 R12:
> ffffffffc08114c8
> [140398.382209] R13: ffffffffc08114c0 R14: 00000000000000fa R15:
> 0000000000000010
> [140398.382223] FS:  0000000000000000(0000) GS:ffff880249640000(0000)
> knlGS:ffff880249640000
> [140398.382225] CS:  e033 DS: 0000 ES: 0000 CR0: 0000000080050033
> [140398.382227] CR2: 00007fb681059eb0 CR3: 000000020a7b9000 CR4:
> 0000000000042660
> [140398.382230] Call Trace:
> [140398.382238]  ida_simple_remove+0x2f/0x45
> [140398.382247]  bcache_device_free+0x8c/0xc4 [bcache]
> [140398.382255]  cached_dev_free+0x6b/0xe1 [bcache]
> [140398.382261]  process_one_work+0x16f/0x281
> [140398.382265]  ? rescuer_thread+0x24e/0x24e
> [140398.382268]  worker_thread+0x1a4/0x257
> [140398.382272]  ? rescuer_thread+0x24e/0x24e
> [140398.382275]  kthread+0xfc/0x101
> [140398.382278]  ? init_completion+0x24/0x24
> [140398.382284]  ret_from_fork+0x25/0x30
> [140398.382287] Code: 00 75 2a 4c 89 f7 e8 79 52 d5 ff 48 8d 75 b0 4c 89
> e2 4c 89 ef e8 03 3a 00 00 eb 11 44 89 fe 48 c7 c7 0a a1 a0 81 e8 c9 79
> d0 ff <0f> ff 48 83 c4 38 5b 41 5c 41 5d 41 5e 41 5f 5d c3 85 f6 79 02
> [140398.382341] ---[ end trace 279bbc0d0aae56cc ]---

Looks like a kernel bug, try the latest vanilla kernel.

Best regards,
Andrew Savchenko