Re: bcache kernel panic

[Matthias Ferdinand <bcache@mfedv.net>]

On Thu, Feb 16, 2023 at 07:06:05PM +0100, Stefan Boehringer wrote:
> Dear Mathias,
> 
> thank you for the update. I look forward to the update. For me, it is a hard
> crash as the screen goes green and I cannot input anything anymore. I still
> hear hard-drive activity, so the system seems to be still up (maybe usable
> via ssh, but haven't tried). I have to perform a hard reset.
> 
> I have not experienced any data loss.

Major nuisance on desktop or notebook machines indeed.

I am not a tumbleweed user, but for the time being you might want to go
back to a slightly older kernel (e.g. on Arch Linux there is the
fast-moving "linux" package and a separate "linux-lts" package).

I haven't seen machines locking up or lose keyboard/screen from a kernel
WARN() (but also don't see many WARNs to begin with...).  Is this
perhaps a hardening feature in SuSE/tumbleweed? Some people want WARN()s
to be handled harshly, I found this discussion on lwn:
    https://lwn.net/Articles/876209/
If so, you could tune it to be less strict until bcache gets patched in
the mainstream kernel.

Matthias

> 
> Thank you, best,
> 
>     Stefan
> 
> On 2/16/23 19:00, Matthias Ferdinand wrote:
> > Hi,
> > 
> > there has been a thread referencing "field-spanning writes" recently:
> > 
> >      https://www.spinics.net/lists/linux-bcache/msg11631.html
> > 
> > I understood this to be some kind of false positive, to be fixed in some
> > later relase of 6.1.x kernels.
> > 
> > Does the system become unusable or is this green-screen just a warning?
> > 
> > Regards
> > Matthias Ferdinand
> > 
> > 
> > On Thu, Feb 16, 2023 at 05:58:15PM +0100, Stefan Boehringer wrote:
> > > Dear bache maintainer,
> > > 
> > > I would like to report a kernel panic for bcache that is unfortunately not
> > > reproducible. I get this error roughly once a week, resulting in a green
> > > screen on my system. Please let me know, if I can provide further
> > > information to fix the bug. Below dmesg output copy-pasted as instructed.
> > > 
> > > Thank you, best,
> > > 
> > >      Stefan
> > > 
> > > 
> > > Feb 15 08:44:49.840548 myhost kernel: ------------[ cut here ]------------
> > > 
> > > Feb 15 08:44:49.840614 myhost kernel: memcpy: detected field-spanning write
> > > (size 264) of single field "&i
> > > ->j" at drivers/md/bcache/journal.c:152 (size 240)
> > > Feb 15 08:44:49.840633 myhost kernel: WARNING: CPU: 7 PID: 755 at
> > > drivers/md/bcache/journal.c:152 journal_
> > > read_bucket+0x3df/0x490 [bcache]
> > > Feb 15 08:44:49.840649 myhost kernel: Modules linked in: snd_hwdep(+) kvm(+)
> > > snd_pcm videobuf2_vmalloc(+)
> > > videobuf2_memops snd_timer videobuf2_v4l2 sr_mod(+) snd real
> > > tek cdrom pcspkr efi_pstore k10temp videobuf2_common i2c_piix4
> > > hid_plantronics(+) irqbypass pcc_cpufreq(-) mdio_devres joydev soundcore
> > > cfg80211 libphy bcache tiny_power_button acpi_cpufreq button fuse configfs
> > > dmi_sysfs ip_tables x_tables btusb btrtl btbcm btintel btmtk bluetooth
> > > hid_generic uas ecdh_generic usbhid usb_storage rfkill amdgpu
> > > crct10dif_pclmul crc32_pclmul polyval_clmulni polyval_generic gf128mul
> > > drm_ttm_helper ttm ghash_clmulni_intel iommu_v2 xhci_pci gpu_sched
> > > sha512_ssse3 xhci_pci_renesas xhci_hcd drm_buddy aesni_intel
> > > drm_display_helper nvme crypto_simd usbcore cryptd cec ccp nvme_core
> > > sp5100_tco rc_core amd_sfh video wmi btrfs blake2b_generic libcrc32c
> > > crc32c_intel xor raid6_pq v4l2loopback(O) videodev mc sg dm_multipath dm_mod
> > > scsi_dh_rdac scsi_dh_emc scsi_dh_alua msr efivarfs
> > > Feb 15 08:44:49.840786 myhost kernel: CPU: 7 PID: 755 Comm: kworker/7:2
> > > Tainted: G           O       6.1.10-1-default #1 openSUSE Tumbleweed
> > > 22576c8b47239465c1855ce27337697dac36c24c
> > > Feb 15 08:44:49.840809 myhost kernel: Hardware name: GIGABYTE
> > > GB-BRR7H-4800/GB-BRR7H-4800, BIOS F5 05/05/2021
> > > Feb 15 08:44:49.840827 myhost kernel: Workqueue: events
> > > register_cache_worker [bcache]
> > > Feb 15 08:44:49.840844 myhost kernel: RIP:
> > > 0010:journal_read_bucket+0x3df/0x490 [bcache]
> > > Feb 15 08:44:49.840860 myhost kernel: Code: 00 00 00 48 89 ee 48 c7 c2 70 c4
> > > cb c0 48 c7 c7 a8 c4 cb c0 4c 89 5c 24 48 48 89 44 24 20 c6 05 21 c8 02 00
> > > 01 e8 3e f5 65 f1 <0f> 0b 4c 8b 5c 24 48 48 8b 44 24 20 e9 6b ff ff ff 44 8b
> > > 74 24 54
> > > Feb 15 08:44:49.840884 myhost kernel: RSP: 0018:ffffb6fe01893c98 EFLAGS:
> > > 00010282
> > > Feb 15 08:44:49.840900 myhost kernel: RAX: 0000000000000000 RBX:
> > > ffff95ebc2a3c000 RCX: 0000000000000027
> > > Feb 15 08:44:49.840915 myhost kernel: RDX: ffff95f2af7e24e8 RSI:
> > > 0000000000000001 RDI: ffff95f2af7e24e0
> > > Feb 15 08:44:49.840932 myhost kernel: RBP: 0000000000000108 R08:
> > > 0000000000000000 R09: ffffb6fe01893b40
> > > Feb 15 08:44:49.840948 myhost kernel: R10: 0000000000000003 R11:
> > > ffff95f2cf2ff228 R12: dead000000000122
> > > Feb 15 08:44:49.840965 myhost kernel: R13: dead000000000100 R14:
> > > ffff95ebc46a8400 R15: ffffb6fe01893e08
> > > Feb 15 08:44:49.840981 myhost kernel: FS:  0000000000000000(0000)
> > > GS:ffff95f2af7c0000(0000) knlGS:0000000000000000
> > > Feb 15 08:44:49.840998 myhost kernel: CS:  0010 DS: 0000 ES: 0000 CR0:
> > > 0000000080050033
> > > Feb 15 08:44:49.841014 myhost kernel: CR2: 00007f166249afe0 CR3:
> > > 000000010323e000 CR4: 0000000000350ee0
> > > Feb 15 08:44:49.841030 myhost kernel: Call Trace:
> > > Feb 15 08:44:49.841047 myhost kernel:  <TASK>
> > > Feb 15 08:44:49.841067 myhost kernel:  ? bch_btree_exit+0x20/0x20 [bcache
> > > f7676faef63111511583961fa9b18ec07deb88c4]
> > > Feb 15 08:44:49.841090 myhost kernel:  bch_journal_read+0x79/0x320 [bcache
> > > f7676faef63111511583961fa9b18ec07deb88c4]
> > > Feb 15 08:44:49.841108 myhost kernel: register_cache_worker+0x99f/0x11c0
> > > [bcache f7676faef63111511583961fa9b18ec07deb88c4]
> > > Feb 15 08:44:49.841125 myhost kernel:  ?
> > > finish_task_switch.isra.0+0x90/0x2d0
> > > Feb 15 08:44:49.841141 myhost kernel:  process_one_work+0x20c/0x3d0
> > > Feb 15 08:44:49.841157 myhost kernel:  worker_thread+0x4a/0x3b0
> > > Feb 15 08:44:49.841173 myhost kernel:  ? process_one_work+0x3d0/0x3d0
> > > Feb 15 08:44:49.841188 myhost kernel:  kthread+0xd7/0x100
> > > Feb 15 08:44:49.841203 myhost kernel:  ? kthread_complete_and_exit+0x20/0x20
> > > Feb 15 08:44:49.841219 myhost kernel:  ret_from_fork+0x1f/0x30
> > > Feb 15 08:44:49.841236 myhost kernel:  </TASK>
> > > Feb 15 08:44:49.841251 myhost kernel: ---[ end trace 0000000000000000 ]---
> > > Feb 15 08:44:49.848553 myhost kernel: sr 1:0:0:0: [sr0] scsi3-mmc drive:
> > > 24x/24x writer dvd-ram cd/rw xa/form2 cdda tray
> > > Feb 15 08:44:49.848843 myhost kernel: cdrom: Uniform CD-ROM driver Revision:
> > > 3.20
> > > Feb 15 08:44:49.872544 myhost kernel: plantronics 0003:047F:1200.0004:
> > > input,hiddev96,hidraw3: USB HID v1.11 Device [Plantronics Plantronics
> > > Calisto 7200] on usb-0000:04:00.0-2.4/input3
> > > Feb 15 08:44:49.876547 myhost kernel: sr 1:0:0:0: Attached scsi CD-ROM sr0
> > > Feb 15 08:44:49.880540 myhost kernel: ------------[ cut here ]------------