Cause of kernel bugs was a defective HDD (/dev/sdd). The kernel BUG:
May 16 07:41:38 nas kernel: [37168.832800] btrfs_dev_stat_print_on_error: 470 callbacks suppressed May 16 07:41:38 nas kernel: [37168.832806] BTRFS error (device sdd): bdev /dev/sdb errs: wr 49293, rd 567248, flush 0, corrupt 0, gen 0 May 16 07:41:38 nas kernel: [37168.832843] BTRFS error (device sdd): bdev /dev/sdf errs: wr 0, rd 537544, flush 0, corrupt 0, gen 0 May 16 07:41:38 nas kernel: [37168.832887] BTRFS error (device sdd): bdev /dev/sdb errs: wr 49293, rd 567249, flush 0, corrupt 0, gen 0 May 16 07:41:38 nas kernel: [37168.832893] BTRFS error (device sdd): bdev /dev/sdf errs: wr 0, rd 537545, flush 0, corrupt 0, gen 0 May 16 07:41:38 nas kernel: [37168.832969] BTRFS error (device sdd): bdev /dev/sdb errs: wr 49293, rd 567250, flush 0, corrupt 0, gen 0 May 16 07:41:38 nas kernel: [37168.832977] BTRFS error (device sdd): bdev /dev/sdf errs: wr 0, rd 537546, flush 0, corrupt 0, gen 0 May 16 07:41:38 nas kernel: [37168.832987] BTRFS error (device sdd): bdev /dev/sdb errs: wr 49293, rd 567251, flush 0, corrupt 0, gen 0 May 16 07:41:38 nas kernel: [37168.832992] BTRFS error (device sdd): bdev /dev/sdf errs: wr 0, rd 537547, flush 0, corrupt 0, gen 0 May 16 07:41:38 nas kernel: [37168.862127] BTRFS error (device sdd): bdev /dev/sdf errs: wr 0, rd 537548, flush 0, corrupt 0, gen 0 May 16 07:41:38 nas kernel: [37168.862188] BTRFS error (device sdd): bdev /dev/sdb errs: wr 49293, rd 567252, flush 0, corrupt 0, gen 0 May 16 07:41:42 nas kernel: [37173.103386] ------------[ cut here ]------------ May 16 07:41:42 nas kernel: [37173.103414] kernel BUG at /home/kernel/COD/linux/fs/btrfs/ctree.c:5201! May 16 07:41:42 nas kernel: [37173.103434] invalid opcode: 0000 [#1] SMP May 16 07:41:42 nas kernel: [37173.103450] Modules linked in: cpuid xt_nat veth xt_addrtype xt_conntrack br_netfilter dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio libcrc32c nvram msr input_leds joydev hid_generic usbhid hid xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack xt_tcpudp bridge stp llc iptable_filter ip_tables x_tables autofs4 eeepc_wmi asus_wmi sparse_keymap intel_rapl x86_pkg_temp_thermal intel_powerclamp kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel cryptd dm_multipath serio_raw snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec bnep rfcomm snd_hda_core bluetooth snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi lpc_ich snd_seq snd_seq_device mei_me snd_timer mei snd soundcore mac_hid shpchp nfsd auth_rpcgss parport_pc nfs_acl ppdev nfs nct6775 hwmon_vid binfmt_misc coretemp lockd grace lp parport sunrpc fscache btrfs xor raid6_pq nls_iso8859_1 dm_mirror dm_region_hash dm_log uas usb_storage i915 e1000e psmouse ahci libahci i2c_algo_bit drm_kms_helper ptp pps_core syscopyarea sysfillrect sysimgblt fb_sys_fops drm video fjes wmi May 16 07:41:42 nas kernel: [37173.103893] CPU: 1 PID: 17784 Comm: btrfs Tainted: G U W 4.5.4-040504-generic #201605120823 May 16 07:41:42 nas kernel: [37173.103916] Hardware name: ASUS All Series/H87I-PLUS, BIOS 2003 11/05/2014 May 16 07:41:42 nas kernel: [37173.103932] task: ffff88020501c240 ti: ffff880161f18000 task.ti: ffff880161f18000 May 16 07:41:42 nas kernel: [37173.103950] RIP: 0010:[<ffffffffc02f4bdd>] [<ffffffffc02f4bdd>] btrfs_search_forward+0x24d/0x330 [btrfs] May 16 07:41:42 nas kernel: [37173.103995] RSP: 0018:ffff880161f1bc38 EFLAGS: 00010246 May 16 07:41:42 nas kernel: [37173.104009] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001 May 16 07:41:42 nas kernel: [37173.104029] RDX: 0000000000000001 RSI: 0000091572628000 RDI: ffff8801ff2fa368 May 16 07:41:42 nas kernel: [37173.104048] RBP: ffff880161f1bc98 R08: 0000091571c00000 R09: 00000915b1c00000 May 16 07:41:42 nas kernel: [37173.104067] R10: ffff880161f1ba30 R11: 0000000000000000 R12: ffff8801d71b6930 May 16 07:41:42 nas kernel: [37173.104086] R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 May 16 07:41:42 nas kernel: [37173.104106] FS: 00007ff94d968900(0000) GS:ffff88021fb00000(0000) knlGS:0000000000000000 May 16 07:41:42 nas kernel: [37173.104129] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 May 16 07:41:42 nas kernel: [37173.104144] CR2: 00007ff94ca80a00 CR3: 0000000214a96000 CR4: 00000000000406e0 May 16 07:41:42 nas kernel: [37173.104164] Stack: May 16 07:41:42 nas kernel: [37173.104173] 00ff880100000000 ffff880161f1bcd7 ffff8800d7699800 c3ff880100000001 May 16 07:41:42 nas kernel: [37173.104203] 0100000000000019 0000000000000000 000000007539a5b8 ffff8801d71b6930 May 16 07:41:42 nas kernel: [37173.104233] ffff880161f1bd30 0000000000000000 ffff880161f1bcd7 0000000000000000 May 16 07:41:42 nas kernel: [37173.104262] Call Trace: May 16 07:41:42 nas kernel: [37173.104329] [<ffffffffc034d81d>] search_ioctl+0xed/0x1b0 [btrfs] May 16 07:41:42 nas kernel: [37173.104388] [<ffffffffc034d952>] btrfs_ioctl_tree_search+0x72/0xc0 [btrfs] May 16 07:41:42 nas kernel: [37173.104434] [<ffffffffc0351f47>] btrfs_ioctl+0x3f7/0x1ea0 [btrfs] May 16 07:41:42 nas kernel: [37173.104457] [<ffffffff811c20d9>] ? handle_mm_fault+0x1349/0x1ae0 May 16 07:41:42 nas kernel: [37173.104481] [<ffffffff81228c61>] do_vfs_ioctl+0xa1/0x5b0 May 16 07:41:42 nas kernel: [37173.104500] [<ffffffff81228c61>] ? do_vfs_ioctl+0xa1/0x5b0 May 16 07:41:42 nas kernel: [37173.104521] [<ffffffff8106aa94>] ? __do_page_fault+0x1b4/0x400 May 16 07:41:42 nas kernel: [37173.104540] [<ffffffff812291e9>] SyS_ioctl+0x79/0x90 May 16 07:41:42 nas kernel: [37173.104562] [<ffffffff81820f72>] entry_SYSCALL_64_fastpath+0x16/0x71 May 16 07:41:42 nas kernel: [37173.104579] Code: 8b 4d a0 48 8b 55 a8 4d 89 f8 48 8b 7d b0 4c 89 e6 e8 78 fb ff ff 85 c0 0f 85 bf 00 00 00 4c 89 e7 e8 58 80 ff ff e9 fa fd ff ff <0f> 0b 48 8d 04 92 43 89 54 ac 40 48 8d 75 bf b9 11 00 00 00 48 May 16 07:41:42 nas kernel: [37173.104746] RIP [<ffffffffc02f4bdd>] btrfs_search_forward+0x24d/0x330 [btrfs] May 16 07:41:42 nas kernel: [37173.104804] RSP <ffff880161f1bc38> May 16 07:41:42 nas kernel: [37173.111041] ---[ end trace c5e9746835476803 ]--- # uname -a Linux nas 4.5.4-040504-generic #201605120823 SMP Thu May 12 12:25:28 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux # btrfs --version btrfs-progs v4.5.3 # btrfs fi show Label: 'RAID' uuid: 3247737b-87f9-4e8c-8db3-2beed50fb104 Total devices 4 FS bytes used 4.21TiB devid 1 size 2.73TiB used 1.66TiB path /dev/sde devid 2 size 2.73TiB used 1.66TiB path /dev/sdb devid 3 size 2.73TiB used 1.66TiB path /dev/sdd devid 4 size 4.55TiB used 3.48TiB path /dev/sdc Label: 'BACKUP' uuid: 6e20fe0c-d4ea-4583-96e4-4f4b9634cb8f Total devices 1 FS bytes used 17.44GiB devid 1 size 232.89GiB used 38.02GiB path /dev/sdf # btrfs fi df /media/RAID/ Data, RAID1: total=4.23TiB, used=4.21TiB System, RAID1: total=32.00MiB, used=624.00KiB Metadata, RAID1: total=6.00GiB, used=4.67GiB GlobalReserve, single: total=512.00MiB, used=0.00B # btrfs scrub status /media/RAID/ scrub status for 3247737b-87f9-4e8c-8db3-2beed50fb104 scrub started at Mon May 16 15:26:35 2016 and finished after 07:13:34 total bytes scrubbed: 8.42TiB with 266185 errors error details: verify=354 csum=265831 corrected errors: 266057, uncorrectable errors: 128, unverified errors: 0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html