Kernel deadlock when using cachefiles.

[Daniel Ribeiro]

Was using both a cifs share and a nfs share at the moment of the crash, both network filesystems get mounted by automount, seems that the bug happened at the cifs automatic umount. Machine froze and stopped responding pings from the network, not even sysrq keys worked, needed a hard power off. Kernel panic (at least what made to syslog) follows:

Mar 1 19:34:04 xps kernel: [ 5497.617469] ------------[ cut here ]------------
Mar 1 19:34:04 xps kernel: [ 5497.617472] kernel BUG at /build/linux-fQ94TU/linux-4.4.0/fs/fscache/cookie.c:639!
Mar 1 19:34:04 xps kernel: [ 5497.617474] invalid opcode: 0000 [#1] SMP
Mar 1 19:34:04 xps kernel: [ 5497.617475] Modules linked in: rpcsec_gss_krb5 nfsv4 nfs drbg ansi_cprng md4 nls_utf8 cifs ccm bnep pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(
OE) dm_cache_smq dm_cache dm_persistent_data dm_bio_prison zram dm_bufio lz4_compress libcrc32c uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 ath3k videobuf2_core btusb v4l2_com
mon btrtl videodev btbcm btintel snd_usb_audio joydev media input_leds bluetooth snd_usbmidi_lib snd_hda_codec_hdmi intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel snd_hd
a_codec_realtek snd_hda_codec_generic kvm dcdbas irqbypass snd_hda_intel arc4 crct10dif_pclmul crc32_pclmul snd_hda_codec ghash_clmulni_intel ath9k aesni_intel snd_hda_core aes_x86_64 lrw sn
d_hwdep gf128mul glue_helper snd_pcm ath9k_common ablk_helper ath9k_hw cryptd snd_seq_midi ath snd_seq_midi_event snd_rawmidi nvidia_uvm(POE) mac80211 snd_seq snd_seq_device snd_timer cfg802
11 serio_raw snd mei_me mei soundcore lpc_ich shpchp mac_hid binfmt_misc cachefiles nfsd fscache auth_rpcgss parport_pc nfs_acl lockd ppdev lp grace sunrpc parport autofs4 btrfs xor uas usb_
storage raid6_pq hid_generic usbhid hid nvidia_drm(POE) nvidia_modeset(POE) nvidia(POE) drm_kms_helper syscopyarea sysfillrect sysimgblt psmouse fb_sys_fops ahci r8169 drm libahci mii video
fjes
Mar 1 19:34:04 xps kernel: [ 5497.617515] CPU: 2 PID: 20454 Comm: umount Tainted: P OE 4.4.0-116-generic #140-Ubuntu
Mar 1 19:34:04 xps kernel: [ 5497.617516] Hardware name: Dell Inc. XPS 8700/0KWVT8, BIOS A08 04/16/2014
Mar 1 19:34:04 xps kernel: [ 5497.617517] task: ffff88034802c600 ti: ffff88029858c000 task.ti: ffff88029858c000
Mar 1 19:34:04 xps kernel: [ 5497.617518] RIP: 0010:[<ffffffffc10a632a>] [<ffffffffc10a632a>] __fscache_cookie_put+0x3a/0x40 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617525] RSP: 0018:ffff88029858fd98 EFLAGS: 00010282
Mar 1 19:34:04 xps kernel: [ 5497.617526] RAX: 0000000000000001 RBX: ffff8802e00244d0 RCX: 0000000000000034
Mar 1 19:34:04 xps kernel: [ 5497.617527] RDX: 0000000000000001 RSI: ffff8802e0024528 RDI: ffff8802e0024528
Mar 1 19:34:04 xps kernel: [ 5497.617528] RBP: ffff88029858fda0 R08: ffff88041ec972c0 R09: 0000000000000001
Mar 1 19:34:04 xps kernel: [ 5497.617528] R10: 0000000000000010 R11: 0000000000000000 R12: ffff8802dde8f000
Mar 1 19:34:04 xps kernel: [ 5497.617529] R13: 0000000000001f39 R14: 0000000000000000 R15: ffff88034802cca0
Mar 1 19:34:04 xps kernel: [ 5497.617531] FS: 00007f93632b5840(0000) GS:ffff88041ec80000(0000) knlGS:0000000000000000
Mar 1 19:34:04 xps kernel: [ 5497.617532] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Mar 1 19:34:04 xps kernel: [ 5497.617533] CR2: 00002205d5e14000 CR3: 0000000293ff6000 CR4: 0000000000160670
Mar 1 19:34:04 xps kernel: [ 5497.617534] Stack:
Mar 1 19:34:04 xps kernel: [ 5497.617535] ffff8802e0024528 ffff88029858fdb8 ffffffffc10a6517 ffff880348d55800
Mar 1 19:34:04 xps kernel: [ 5497.617536] ffff88029858fdd0 ffffffffc1854232 ffff880348d55800 ffff88029858fdf8
Mar 1 19:34:04 xps kernel: [ 5497.617538] ffffffffc182d3e0 ffff8800a1c7ce40 ffff880348d55000 ffff880348d55008
Mar 1 19:34:04 xps kernel: [ 5497.617548] Call Trace:
Mar 1 19:34:04 xps kernel: [ 5497.617552] [<ffffffffc10a6517>] __fscache_relinquish_cookie+0x87/0x120 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617572] [<ffffffffc1854232>] cifs_fscache_release_super_cookie+0x32/0x90 [cifs]
Mar 1 19:34:04 xps kernel: [ 5497.617580] [<ffffffffc182d3e0>] cifs_put_tcon+0x100/0x180 [cifs]
Mar 1 19:34:04 xps kernel: [ 5497.617587] [<ffffffffc182d4a7>] cifs_put_tlink+0x47/0x60 [cifs]
Mar 1 19:34:04 xps kernel: [ 5497.617595] [<ffffffffc182eb1b>] cifs_umount+0x5b/0xc0 [cifs]
Mar 1 19:34:04 xps kernel: [ 5497.617602] [<ffffffffc181a01e>] cifs_kill_sb+0x1e/0x30 [cifs]
Mar 1 19:34:04 xps kernel: [ 5497.617605] [<ffffffff812164b8>] deactivate_locked_super+0x48/0x80
Mar 1 19:34:04 xps kernel: [ 5497.617607] [<ffffffff8121699c>] deactivate_super+0x5c/0x60
Mar 1 19:34:04 xps kernel: [ 5497.617609] [<ffffffff81234b4f>] cleanup_mnt+0x3f/0x90
Mar 1 19:34:04 xps kernel: [ 5497.617611] [<ffffffff81234be2>] __cleanup_mnt+0x12/0x20
Mar 1 19:34:04 xps kernel: [ 5497.617613] [<ffffffff810a14e6>] task_work_run+0x86/0xb0
Mar 1 19:34:04 xps kernel: [ 5497.617616] [<ffffffff81003242>] exit_to_usermode_loop+0xc2/0xd0
Mar 1 19:34:04 xps kernel: [ 5497.617618] [<ffffffff81003c7e>] syscall_return_slowpath+0x4e/0x60
Mar 1 19:34:04 xps kernel: [ 5497.617621] [<ffffffff8184f170>] int_ret_from_sys_call+0x25/0x9f
Mar 1 19:34:04 xps kernel: [ 5497.617622] Code: 7e 18 00 48 8b 5e 28 75 22 48 8b 3d 71 83 00 00 e8 4c cb 14 c0 48 85 db 74 0e 8b 03 85 c0 7e 0d 48 89 de f0 ff 0b 74 d6 5b 5d c3 <0f> 0b 0f 0b 66 90 0f 1f 44 00 00 55 48 85 f6 48 89 e5 41 57 41
Mar 1 19:34:04 xps kernel: [ 5497.617640] RIP [<ffffffffc10a632a>] __fscache_cookie_put+0x3a/0x40 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617643] RSP <ffff88029858fd98>
Mar 1 19:34:04 xps kernel: [ 5497.617645] ---[ end trace 13ab4a22ef04578f ]---
Mar 1 19:34:04 xps kernel: [ 5497.617651] ------------[ cut here ]------------
Mar 1 19:34:04 xps kernel: [ 5497.617653] kernel BUG at /build/linux-fQ94TU/linux-4.4.0/fs/fscache/internal.h:321!
Mar 1 19:34:04 xps kernel: [ 5497.617654] invalid opcode: 0000 [#2] SMP
Mar 1 19:34:04 xps kernel: [ 5497.617656] Modules linked in: rpcsec_gss_krb5 nfsv4 nfs drbg ansi_cprng md4 nls_utf8 cifs ccm bnep pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) dm_cache_smq dm_cache dm_persistent_data dm_bio_prison zram dm_bufio lz4_compress libcrc32c uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 ath3k videobuf2_core btusb v4l2_common btrtl videodev btbcm btintel snd_usb_audio joydev media input_leds bluetooth snd_usbmidi_lib snd_hda_codec_hdmi intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel snd_hda_codec_realtek snd_hda_codec_generic kvm dcdbas irqbypass snd_hda_intel arc4 crct10dif_pclmul crc32_pclmul snd_hda_codec ghash_clmulni_intel ath9k aesni_intel snd_hda_core aes_x86_64 lrw snd_hwdep gf128mul glue_helper snd_pcm ath9k_common ablk_helper ath9k_hw cryptd snd_seq_midi ath snd_seq_midi_event snd_rawmidi nvidia_uvm(POE) mac80211 snd_seq snd_seq_device snd_timer cfg80211 serio_raw snd mei_me mei soundcore lpc_ich shpchp mac_hid binfmt_misc cachefiles nfsd fscache auth_rpcgss parport_pc nfs_acl lockd ppdev lp grace sunrpc parport autofs4 btrfs xor uas usb_storage raid6_pq hid_generic usbhid hid nvidia_drm(POE) nvidia_modeset(POE) nvidia(POE) drm_kms_helper syscopyarea sysfillrect sysimgblt psmouse fb_sys_fops ahci r8169 drm libahci mii video fjes
Mar 1 19:34:04 xps kernel: [ 5497.617698] CPU: 1 PID: 11898 Comm: kworker/u16:3 Tainted: P D OE 4.4.0-116-generic #140-Ubuntu
Mar 1 19:34:04 xps kernel: [ 5497.617699] Hardware name: Dell Inc. XPS 8700/0KWVT8, BIOS A08 04/16/2014
Mar 1 19:34:04 xps kernel: [ 5497.617703] Workqueue: fscache_object fscache_object_work_func [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617704] task: ffff88032ae16200 ti: ffff8802bd36c000 task.ti: ffff8802bd36c000
Mar 1 19:34:04 xps kernel: [ 5497.617705] RIP: 0010:[<ffffffffc10a6c93>] [<ffffffffc10a6c93>] fscache_object_destroy+0x43/0x50 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617709] RSP: 0018:ffff8802bd36fdc0 EFLAGS: 00010246
Mar 1 19:34:04 xps kernel: [ 5497.617710] RAX: ffff8802e0024528 RBX: ffff8802e00fef00 RCX: 000000bc00000000
Mar 1 19:34:04 xps kernel: [ 5497.617711] RDX: 0000000000000000 RSI: ffff8802e00ff010 RDI: ffff8802e00fef00
Mar 1 19:34:04 xps kernel: [ 5497.617712] RBP: ffff8802bd36fdd8 R08: ffff8802e00ca728 R09: 0000000000000000
Mar 1 19:34:04 xps kernel: [ 5497.617713] R10: ffff8802e00ce5a8 R11: 0000000000000000 R12: ffff880405ddf200
Mar 1 19:34:04 xps kernel: [ 5497.617714] R13: ffff8802e00fef90 R14: ffffffffc10ab6a0 R15: ffff8802e00fef90
Mar 1 19:34:04 xps kernel: [ 5497.617715] FS: 0000000000000000(0000) GS:ffff88041ec40000(0000) knlGS:0000000000000000
Mar 1 19:34:04 xps kernel: [ 5497.617717] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Mar 1 19:34:04 xps kernel: [ 5497.617718] CR2: 00007ff648225000 CR3: 0000000002e0a000 CR4: 0000000000160670
Mar 1 19:34:04 xps kernel: [ 5497.617719] Stack:
Mar 1 19:34:04 xps kernel: [ 5497.617719] ffffffffc111fea2 ffff8802e00fef00 000000000000006d ffff8802bd36fde8
Mar 1 19:34:04 xps kernel: [ 5497.617721] ffffffffc10a6a00 ffff8802bd36fe18 ffffffffc10a7521 ffff8802fa79a3c0
Mar 1 19:34:04 xps kernel: [ 5497.617723] ffff88040e19b400 ffff880034de3700 0000000000000200 ffff8802bd36fe58
Mar 1 19:34:04 xps kernel: [ 5497.617725] Call Trace:
Mar 1 19:34:04 xps kernel: [ 5497.617728] [<ffffffffc111fea2>] ? cachefiles_put_object+0xd2/0x270 [cachefiles]
Mar 1 19:34:04 xps kernel: [ 5497.617731] [<ffffffffc10a6a00>] fscache_put_object+0x20/0x30 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617734] [<ffffffffc10a7521>] fscache_object_work_func+0x181/0x200 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617737] [<ffffffff8109ca0b>] process_one_work+0x16b/0x490
Mar 1 19:34:04 xps kernel: [ 5497.617739] [<ffffffff8109cd7b>] worker_thread+0x4b/0x4d0
Mar 1 19:34:04 xps kernel: [ 5497.617740] [<ffffffff8109cd30>] ? process_one_work+0x490/0x490
Mar 1 19:34:04 xps kernel: [ 5497.617742] [<ffffffff810a30f7>] kthread+0xe7/0x100
Mar 1 19:34:04 xps kernel: [ 5497.617744] [<ffffffff810a3010>] ? kthread_create_on_node+0x1e0/0x1e0
Mar 1 19:34:04 xps kernel: [ 5497.617746] [<ffffffff8184f435>] ret_from_fork+0x55/0x80
Mar 1 19:34:04 xps kernel: [ 5497.617747] [<ffffffff810a3010>] ? kthread_create_on_node+0x1e0/0x1e0
Mar 1 19:34:04 xps kernel: [ 5497.617748] Code: 89 fb f0 ff 08 74 0e 48 c7 83 80 00 00 00 00 00 00 00 5b 5d c3 48 89 c7 e8 6b f6 ff ff 48 c7 83 80 00 00 00 00 00 00 00 5b 5d c3 <0f> 0b 90 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89
Mar 1 19:34:04 xps kernel: [ 5497.617767] RIP [<ffffffffc10a6c93>] fscache_object_destroy+0x43/0x50 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617770] RSP <ffff8802bd36fdc0>
Mar 1 19:34:04 xps kernel: [ 5497.617771] ---[ end trace 13ab4a22ef045790 ]---
Mar 1 19:34:04 xps kernel: [ 5497.617783] BUG: unable to handle kernel paging request at ffffffffffffffd8
Mar 1 19:34:04 xps kernel: [ 5497.617785] IP: [<ffffffff810a37b0>] kthread_data+0x10/0x20
Mar 1 19:34:04 xps kernel: [ 5497.617787] PGD 2e0f067 PUD 2e11067 PMD 0
Mar 1 19:34:04 xps kernel: [ 5497.617788] Oops: 0000 [#3] SMP
Mar 1 19:34:04 xps kernel: [ 5497.617789] Modules linked in: rpcsec_gss_krb5 nfsv4 nfs drbg ansi_cprng md4 nls_utf8 cifs ccm bnep pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) dm_cache_smq dm_cache dm_persistent_data dm_bio_prison zram dm_bufio lz4_compress libcrc32c uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 ath3k videobuf2_core btusb v4l2_common btrtl videodev btbcm btintel snd_usb_audio joydev media input_leds bluetooth snd_usbmidi_lib snd_hda_codec_hdmi intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel snd_hda_codec_realtek snd_hda_codec_generic kvm dcdbas irqbypass snd_hda_intel arc4 crct10dif_pclmul crc32_pclmul snd_hda_codec ghash_clmulni_intel ath9k aesni_intel snd_hda_core aes_x86_64 lrw snd_hwdep gf128mul glue_helper snd_pcm ath9k_common ablk_helper ath9k_hw cryptd snd_seq_midi ath snd_seq_midi_event snd_rawmidi nvidia_uvm(POE) mac80211 snd_seq snd_seq_device snd_timer cfg80211 serio_raw snd mei_me mei soundcore lpc_ich shpchp mac_hid binfmt_misc cachefiles nfsd fscache auth_rpcgss parport_pc nfs_acl lockd ppdev lp grace sunrpc parport autofs4 btrfs xor uas usb_storage raid6_pq hid_generic usbhid hid nvidia_drm(POE) nvidia_modeset(POE) nvidia(POE) drm_kms_helper syscopyarea sysfillrect sysimgblt psmouse fb_sys_fops ahci r8169 drm libahci mii video fjes
Mar 1 19:34:04 xps kernel: [ 5497.617831] CPU: 1 PID: 11898 Comm: kworker/u16:3 Tainted: P D OE 4.4.0-116-generic #140-Ubuntu
Mar 1 19:34:04 xps kernel: [ 5497.617831] Hardware name: Dell Inc. XPS 8700/0KWVT8, BIOS A08 04/16/2014
Mar 1 19:34:04 xps kernel: [ 5497.617838] task: ffff88032ae16200 ti: ffff8802bd36c000 task.ti: ffff8802bd36c000
Mar 1 19:34:04 xps kernel: [ 5497.617839] RIP: 0010:[<ffffffff810a37b0>] [<ffffffff810a37b0>] kthread_data+0x10/0x20
Mar 1 19:34:04 xps kernel: [ 5497.617841] RSP: 0018:ffff8802bd36fa98 EFLAGS: 00010002
Mar 1 19:34:04 xps kernel: [ 5497.617842] RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff82112e80
Mar 1 19:34:04 xps kernel: [ 5497.617843] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff88032ae16200
Mar 1 19:34:04 xps kernel: [ 5497.617844] RBP: ffff8802bd36fa98 R08: 00000000ffffffff R09: 0000000000000000
Mar 1 19:34:04 xps kernel: [ 5497.617845] R10: ffff88032ae16260 R11: 0000000000059800 R12: 0000000000000000
Mar 1 19:34:04 xps kernel: [ 5497.617846] R13: 00000000000172c0 R14: ffff88032ae16200 R15: ffff88041ec572c0
Mar 1 19:34:04 xps kernel: [ 5497.617847] FS: 0000000000000000(0000) GS:ffff88041ec40000(0000) knlGS:0000000000000000
Mar 1 19:34:04 xps kernel: [ 5497.617848] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Mar 1 19:34:04 xps kernel: [ 5497.617849] CR2: 0000000000000028 CR3: 0000000002e0a000 CR4: 0000000000160670
Mar 1 19:34:04 xps kernel: [ 5497.617850] Stack:
Mar 1 19:34:04 xps kernel: [ 5497.617851] ffff8802bd36fab0 ffffffff8109de11 ffff88041ec572c0 ffff8802bd36fb00
Mar 1 19:34:04 xps kernel: [ 5497.617852] ffffffff8184ab8e ffff88040510f148 ffff880200000001 ffff88032ae16200
Mar 1 19:34:04 xps kernel: [ 5497.617854] ffff8802bd370000 ffff88032ae168d0 ffff8802bd36f6b0 0000000000000000
Mar 1 19:34:04 xps kernel: [ 5497.617856] Call Trace:
Mar 1 19:34:04 xps kernel: [ 5497.617858] [<ffffffff8109de11>] wq_worker_sleeping+0x11/0x90
Mar 1 19:34:04 xps kernel: [ 5497.617860] [<ffffffff8184ab8e>] __schedule+0x54e/0x7d0
Mar 1 19:34:04 xps kernel: [ 5497.617862] [<ffffffff8184ae45>] schedule+0x35/0x80
Mar 1 19:34:04 xps kernel: [ 5497.617865] [<ffffffff81086248>] do_exit+0x778/0xb00
Mar 1 19:34:04 xps kernel: [ 5497.617869] [<ffffffff81031cf1>] oops_end+0xa1/0xd0
Mar 1 19:34:04 xps kernel: [ 5497.617871] [<ffffffff810321ab>] die+0x4b/0x70
Mar 1 19:34:04 xps kernel: [ 5497.617872] [<ffffffff8102f131>] do_trap+0xb1/0x140
Mar 1 19:34:04 xps kernel: [ 5497.617874] [<ffffffff8102f4b9>] do_error_trap+0x89/0x110
Mar 1 19:34:04 xps kernel: [ 5497.617877] [<ffffffffc10a6c93>] ? fscache_object_destroy+0x43/0x50 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617880] [<ffffffff810c02d3>] ? load_balance+0x1d3/0x980
Mar 1 19:34:04 xps kernel: [ 5497.617882] [<ffffffff8102fa20>] do_invalid_op+0x20/0x30
Mar 1 19:34:04 xps kernel: [ 5497.617884] [<ffffffff818512ee>] invalid_op+0x1e/0x30
Mar 1 19:34:04 xps kernel: [ 5497.617887] [<ffffffffc10a6c93>] ? fscache_object_destroy+0x43/0x50 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617889] [<ffffffffc111fea2>] ? cachefiles_put_object+0xd2/0x270 [cachefiles]
Mar 1 19:34:04 xps kernel: [ 5497.617892] [<ffffffffc10a6a00>] fscache_put_object+0x20/0x30 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617894] [<ffffffffc10a7521>] fscache_object_work_func+0x181/0x200 [fscache]
Mar 1 19:34:04 xps kernel: [ 5497.617896] [<ffffffff8109ca0b>] process_one_work+0x16b/0x490
Mar 1 19:34:04 xps kernel: [ 5497.617898] [<ffffffff8109cd7b>] worker_thread+0x4b/0x4d0
Mar 1 19:34:04 xps kernel: [ 5497.617900] [<ffffffff8109cd30>] ? process_one_work+0x490/0x490
Mar 1 19:34:04 xps kernel: [ 5497.617901] [<ffffffff810a30f7>] kthread+0xe7/0x100
Mar 1 19:34:04 xps kernel: [ 5497.617903] [<ffffffff810a3010>] ? kthread_create_on_node+0x1e0/0x1e0
Mar 1 19:34:04 xps kernel: [ 5497.617904] [<ffffffff8184f435>] ret_from_fork+0x55/0x80
Mar 1 19:34:04 xps kernel: [ 5497.617906] [<ffffffff810a3010>] ? kthread_create_on_node+0x1e0/0x1e0
Mar 1 19:34:04 xps kernel: [ 5497.617907] Code: c7 10 d8 cb 81 e8 91 fa fd ff e9 a0 fe ff ff 66 90 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 8b 87 18 05 00 00 55 48 89 e5 <48> 8b 40 d8 5d c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00
Mar 1 19:34:04 xps kernel: [ 5497.617925] RIP [<ffffffff810a37b0>] kthread_data+0x10/0x20
Mar 1 19:34:04 xps kernel: [ 5497.617927] RSP <ffff8802bd36fa98>
Mar 1 19:34:04 xps kernel: [ 5497.617928] CR2: ffffffffffffffd8
Mar 1 19:34:04 xps kernel: [ 5497.617929] ---[ end trace 13ab4a22ef045791 ]---
Mar 1 19:34:04 xps kernel: [ 5497.617929] Fixing recursive fault but reboot is needed!

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-116-generic 4.4.0-116.140
ProcVersionSignature: Ubuntu 4.4.0-116.140-generic 4.4.98
Uname: Linux 4.4.0-116-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC2: wyrm 2698 F.... pulseaudio
 /dev/snd/controlC1: wyrm 2698 F.... pulseaudio
 /dev/snd/controlC0: wyrm 2698 F.... pulseaudio
CurrentDesktop: Unity
Date: Thu Mar 1 20:03:25 2018
EcryptfsInUse: Yes
HibernationDevice: RESUME=UUID=2e7ce3a8-6ee9-4960-b4b8-902388470b71
InstallationDate: Installed on 2016-06-08 (631 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
MachineType: Dell Inc. XPS 8700
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/@/boot/vmlinuz-4.4.0-116-generic.efi.signed root=UUID=54159e36-67b8-448d-90d2-acbb0f853d63 ro rootflags=subvol=@ vga=0 rdblacklist=nouveau nouveau.modeset=0 quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-116-generic N/A
 linux-backports-modules-4.4.0-116-generic N/A
 linux-firmware 1.157.16
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/16/2014
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A08
dmi.board.name: 0KWVT8
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 3
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA08:bd04/16/2014:svnDellInc.:pnXPS8700:pvr:rvnDellInc.:rn0KWVT8:rvrA00:cvnDellInc.:ct3:cvr:
dmi.product.name: XPS 8700
dmi.sys.vendor: Dell Inc.

[Daniel Ribeiro (drwyrm)]

cachefilesd.conf:
dir /cache/fscache
tag mycache
brun 10%
bcull 7%
bstop 3%
frun 10%
fcull 7%
fstop 3%
secctx system_u:system_r:cachefiles_kernel_t:s0

/cache is a separate ext4 partition, currently only cachefiles using it.

the cifs mount was using the following options:
//htpc/rootfs/ on /smb/htpc type cifs (rw,relatime,vers=1.0,cache=none,username=wyrm,domain=HTPC,uid=0,noforceuid,gid=0,noforcegid,addr=192.168.1.5,unix,posixpaths,serverino,acl,fsc,noperm,rsize=65536,wsize=65536,echo_interval=60,actimeo=1,user=wyrm)

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.16 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.16-rc4

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]