Bug 196697

Summary: Module 'nbd' crashes
Product: Other Reporter: marek
Component: ModulesAssignee: other_modules
Status: NEW ---    
Severity: normal    
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 4.11.11-300.fc26.x86_64 Subsystem:
Regression: No Bisected commit-id:

Description marek 2017-08-18 03:31:26 UTC 
11196.270438] ------------[ cut here ]------------
[11196.270440] kernel BUG at fs/buffer.c:3099!
[11196.270447] invalid opcode: 0000 [#1] SMP
[11196.270450] Modules linked in: nls_utf8 hfsplus hfs vfat fat isofs nbd btrfs xor raid6_pq xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 nf_conntrack_netbios_ns nf_conntrack_broadcast xt_CT ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 tun nf_nat_ipv4 bridge nf_nat nf_conntrack stp libcrc32c llc iptable_mangle iptable_raw iscsi_target_mod iptable_security ebtable_filter target_core_mod ebtables vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) ip6table_filter ip6_tables vboxdrv(OE) nct7904 sunrpc intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm joydev iTCO_wdt iTCO_vendor_support
[11196.270522]  irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel intel_cstate ses enclosure intel_uncore intel_rapl_perf mei_me i2c_i801 lpc_ich mei ioatdma ipmi_ssif tpm_tis shpchp tpm_tis_core ipmi_si ipmi_devintf ipmi_msghandler tpm wmi drm_kms_helper crc32c_intel mpt3sas ttm igb drm ptp pps_core raid_class dca scsi_transport_sas i2c_algo_bit [last unloaded: nbd]
[11196.270565] CPU: 11 PID: 27923 Comm: umount Tainted: G           OE   4.12.5-300.fc26.x86_64 #1
[11196.270567] Hardware name: Supermicro X9DRD-7LN4F(-JBOD)/X9DRD-EF/X9DRD-7LN4F, BIOS 3.2 01/16/2015
[11196.270571] task: ffff8ffeb5d525c0 task.stack: ffffa6128c9dc000
[11196.270584] RIP: 0010:submit_bh_wbc+0x155/0x160
[11196.270586] RSP: 0018:ffffa6128c9dfd60 EFLAGS: 00010246
[11196.270590] RAX: 0000000000000005 RBX: ffff9006b33be958 RCX: 0000000000000000
[11196.270592] RDX: ffff9006b33be958 RSI: 0000000000020800 RDI: 0000000000000001
[11196.270594] RBP: ffffa6128c9dfd88 R08: ffffffff80000000 R09: 00000000ffffffff
[11196.270597] R10: 00000000000031b0 R11: 000000000001eb41 R12: 0000000000020800
[11196.270599] R13: ffffffff8205a200 R14: ffff9006a70b2400 R15: 0000000000238588
[11196.270602] FS:  00007f30b7c194c0(0000) GS:ffff9006df2c0000(0000) knlGS:0000000000000000
[11196.270605] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[11196.270607] CR2: 00000083ba978778 CR3: 0000001051020000 CR4: 00000000001406e0
[11196.270610] Call Trace:
[11196.270622]  __sync_dirty_buffer+0x52/0xf0
[11196.270635]  ext4_commit_super+0x22b/0x2c0
[11196.270639]  ext4_put_super+0xe9/0x3b0
[11196.270645]  generic_shutdown_super+0x6f/0x110
[11196.270649]  kill_block_super+0x27/0x50
[11196.270652]  deactivate_locked_super+0x43/0x70
[11196.270655]  deactivate_super+0x3f/0x60
[11196.270663]  cleanup_mnt+0x3f/0x80
[11196.270667]  __cleanup_mnt+0x12/0x20
[11196.270676]  task_work_run+0x76/0x90
[11196.270683]  exit_to_usermode_loop+0xab/0xb0
[11196.270688]  syscall_return_slowpath+0x8f/0xa0
[11196.270698]  entry_SYSCALL_64_fastpath+0xa3/0xa5
[11196.270704] RIP: 0033:0x7f30b6c7bbc7
[11196.270706] RSP: 002b:00007ffd25c088f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[11196.270709] RAX: 0000000000000000 RBX: 00000083ba96e050 RCX: 00007f30b6c7bbc7
[11196.270712] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 00000083ba976360
[11196.270714] RBP: 00000083ba976360 R08: 0000000000000000 R09: 00007ffd25c07838
[11196.270716] R10: 00000083ba9765e0 R11: 0000000000000246 R12: 00007f30b7a0d184
[11196.270718] R13: 0000000000000000 R14: 00000083ba96e230 R15: 0000000000000000
[11196.270721] Code: 89 ef 44 09 f7 41 89 7c 24 14 4c 89 e7 e8 94 d0 13 00 5b 31 c0 41 5c 41 5d 41 5e 41 5f 5d c3 f0 80 62 01 f7 e9 19 ff ff ff 0f 0b <0f> 0b 0f 0b 0f 0b 0f 0b 0f 0b 90 0f 1f 44 00 00 55 49 89 f9 48 
[11196.270772] RIP: submit_bh_wbc+0x155/0x160 RSP: ffffa6128c9dfd60
[11196.270777] ---[ end trace 30e6bf3720fe03ac ]---
Comment 1 marek 2017-08-18 03:33:31 UTC 
I think this has to do with nbd, as it occurrs during shutdown of an nbd and nbdkit based server.
Comment 2 marek 2017-08-18 03:56:10 UTC 
I can reproduce by issuing 

sudo umount /dev/nbd0

The error message above is then generated. BTW, I cannot remove nbd from the kernel:
user% sudo modprobe -r nbd
modprobe: FATAL: Module nbd is in use.
user%  lsmod |grep nbd
nbd                    32768  2