Comment 13 for bug 760595

This is still a problem in 2019? I've attached my Ubuntu 18.04.2 desktop to an Active Directory using:

https://help.ubuntu.com/lts/serverguide/sssd-ad.html.en

Everything appears to work perfectly until some sort of failure - I can reproduce it under high load, or just waiting..., I'll try pulling the network cable next. After than, any access to the mount, causes a hang for that process.

dmesg offers:
[91051.156847] CIFS VFS: Send error in SessSetup = -126
[91051.156860] CIFS VFS: Send error in SessSetup = -126
[91229.140916] INFO: task kworker/3:1:11816 blocked for more than 120 seconds.
[91229.140922] Not tainted 4.18.0-18-generic #19~18.04.1-Ubuntu
[91229.140924] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[91229.140927] kworker/3:1 D 0 11816 2 0x80000000
[91229.140961] Workqueue: cifsiod smb2_reconnect_server [cifs]
[91229.140963] Call Trace:
[91229.140969] __schedule+0x2b7/0x880
[91229.140972] schedule+0x2c/0x80
[91229.140974] schedule_preempt_disabled+0xe/0x10
[91229.140976] __mutex_lock.isra.4+0x18c/0x4d0
[91229.140980] __mutex_lock_slowpath+0x13/0x20
[91229.140981] ? __mutex_lock_slowpath+0x13/0x20
[91229.140983] mutex_lock+0x2f/0x40
[91229.141003] smb2_reconnect+0xed/0x4b0 [cifs]
[91229.141006] ? __switch_to_asm+0x34/0x70
[91229.141008] ? __switch_to_asm+0x40/0x70
[91229.141010] ? __switch_to_asm+0x34/0x70
[91229.141012] ? __switch_to_asm+0x40/0x70
[91229.141015] ? __switch_to_asm+0x34/0x70
[91229.141017] ? __switch_to_asm+0x40/0x70
[91229.141019] ? __switch_to_asm+0x34/0x70
[91229.141036] smb2_reconnect_server+0x190/0x2d0 [cifs]
[91229.141041] process_one_work+0x1fd/0x3f0
[91229.141044] worker_thread+0x34/0x410
[91229.141047] kthread+0x121/0x140
[91229.141050] ? process_one_work+0x3f0/0x3f0
[91229.141053] ? kthread_create_worker_on_cpu+0x70/0x70
[91229.141055] ret_from_fork+0x35/0x40
[91229.141058] INFO: task bash:11900 blocked for more than 120 seconds.
[91229.141061] Not tainted 4.18.0-18-generic #19~18.04.1-Ubuntu
[91229.141062] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[91229.141064] bash D 0 11900 2685 0x80000000
[91229.141066] Call Trace:
[91229.141069] __schedule+0x2b7/0x880
[91229.141071] schedule+0x2c/0x80
[91229.141073] schedule_preempt_disabled+0xe/0x10
[91229.141074] __mutex_lock.isra.4+0x18c/0x4d0
[91229.141092] ? cifs_small_buf_release+0x1a/0x70 [cifs]
[91229.141109] ? SMB2_auth_kerberos+0x92/0x190 [cifs]
[91229.141112] __mutex_lock_slowpath+0x13/0x20
[91229.141114] ? __mutex_lock_slowpath+0x13/0x20
[91229.141115] mutex_lock+0x2f/0x40
[91229.141130] cifs_mark_open_files_invalid+0x5b/0xa0 [cifs]
[91229.141146] smb2_reconnect+0x135/0x4b0 [cifs]
[91229.141163] smb2_plain_req_init+0x34/0x270 [cifs]
[91229.141180] SMB2_open+0xe9/0xc90 [cifs]
[91229.141185] ? get_page_from_freelist+0xcd0/0x1430
[91229.141187] ? get_page_from_freelist+0x1420/0x1430
[91229.141205] open_shroot+0x16c/0x210 [cifs]
[91229.141221] ? open_shroot+0x16c/0x210 [cifs]
[91229.141239] smb2_open_op_close+0x26f/0x2e0 [cifs]
[91229.141242] ? alloc_pages_current+0x6a/0xe0
[91229.141259] smb2_query_path_info+0x74/0xf0 [cifs]
[91229.141277] cifs_get_inode_info+0x328/0xaf0 [cifs]
[91229.141293] ? build_path_from_dentry_optional_prefix+0x103/0x430 [cifs]
[91229.141310] cifs_revalidate_dentry_attr+0xe9/0x3d0 [cifs]
[91229.141326] cifs_getattr+0x5b/0x1a0 [cifs]
[91229.141329] ? common_perm_cond+0x4c/0x70
[91229.141332] vfs_getattr_nosec+0x73/0x90
[91229.141335] vfs_getattr+0x36/0x40
[91229.141337] vfs_statx+0x8d/0xe0
[91229.141340] ? kzfree+0x2d/0x40
[91229.141343] __do_sys_newstat+0x3d/0x70
[91229.141346] __x64_sys_newstat+0x16/0x20
[91229.141349] do_syscall_64+0x5a/0x120
[91229.141352] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[91229.141354] RIP: 0033:0x7f2d88ec1775
[91229.141355] Code: Bad RIP value.
[91229.141361] RSP: 002b:00007fff876b7948 EFLAGS: 00000246 ORIG_RAX: 0000000000000004
[91229.141364] RAX: ffffffffffffffda RBX: 00005562d1bec830 RCX: 00007f2d88ec1775
[91229.141365] RDX: 00007fff876b7950 RSI: 00007fff876b7950 RDI: 00005562d1bec830
[91229.141366] RBP: 00005562d1bf09f0 R08: 0000000000000000 R09: 00007f2d8919dc40
[91229.141368] R10: 0000000000000007 R11: 0000000000000246 R12: 00005562d1c2d9f0
[91229.141369] R13: 00005562d04ee610 R14: 0000000000000000 R15: 0000000000000000
[91229.141372] INFO: task umount:11941 blocked for more than 120 seconds.
[91229.141374] Not tainted 4.18.0-18-generic #19~18.04.1-Ubuntu
[91229.141375] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[91229.141377] umount D 0 11941 9025 0x00000000
[91229.141379] Call Trace:
[91229.141382] __schedule+0x2b7/0x880
[91229.141384] schedule+0x2c/0x80
[91229.141385] schedule_preempt_disabled+0xe/0x10
[91229.141387] __mutex_lock.isra.4+0x18c/0x4d0
[91229.141390] __mutex_lock_slowpath+0x13/0x20
[91229.141392] ? __mutex_lock_slowpath+0x13/0x20
[91229.141393] mutex_lock+0x2f/0x40
[91229.141411] open_shroot+0x45/0x210 [cifs]
[91229.141429] smb2_open_op_close+0x26f/0x2e0 [cifs]
[91229.141431] ? alloc_pages_current+0x6a/0xe0
[91229.141448] smb2_query_path_info+0x74/0xf0 [cifs]
[91229.141465] cifs_get_inode_info+0x328/0xaf0 [cifs]
[91229.141481] ? build_path_from_dentry_optional_prefix+0x103/0x430 [cifs]
[91229.141497] cifs_revalidate_dentry_attr+0xe9/0x3d0 [cifs]
[91229.141513] cifs_getattr+0x5b/0x1a0 [cifs]
[91229.141515] ? common_perm_cond+0x4c/0x70
[91229.141517] vfs_getattr_nosec+0x73/0x90
[91229.141520] vfs_getattr+0x36/0x40
[91229.141522] vfs_statx+0x8d/0xe0
[91229.141525] ? kzfree+0x2d/0x40
[91229.141527] __do_sys_newfstatat+0x35/0x70
[91229.141531] __x64_sys_newfstatat+0x1e/0x20
[91229.141533] do_syscall_64+0x5a/0x120
[91229.141536] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[91229.141537] RIP: 0033:0x7f397a7f8929
[91229.141538] Code: Bad RIP value.
[91229.141541] RSP: 002b:00007ffebfee0368 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
[91229.141543] RAX: ffffffffffffffda RBX: 000056553c7e3a40 RCX: 00007f397a7f8929
[91229.141545] RDX: 00007ffebfee0420 RSI: 000056553c7e3c20 RDI: 00000000ffffffff
[91229.141546] RBP: 0000000000000000 R08: 0000000000000800 R09: 0000000000000001
[91229.141547] R10: 0000000000000800 R11: 0000000000000246 R12: 000056553c7e3c20
[91229.141549] R13: 0000000000000001 R14: 00000000ffffffff R15: 0000000000000000
[91349.972893] INFO: task kworker/3:1:11816 blocked for more than 120 seconds.
[91349.972899] Not tainted 4.18.0-18-generic #19~18.04.1-Ubuntu
[91349.972901] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[91349.972904] kworker/3:1 D 0 11816 2 0x80000000
[91349.972942] Workqueue: cifsiod smb2_reconnect_server [cifs]
[91349.972945] Call Trace:
[91349.972953] __schedule+0x2b7/0x880
[91349.972956] schedule+0x2c/0x80
[91349.972958] schedule_preempt_disabled+0xe/0x10
[91349.972961] __mutex_lock.isra.4+0x18c/0x4d0
[91349.972965] __mutex_lock_slowpath+0x13/0x20
[91349.972968] ? __mutex_lock_slowpath+0x13/0x20
[91349.972970] mutex_lock+0x2f/0x40
[91349.972993] smb2_reconnect+0xed/0x4b0 [cifs]
[91349.972997] ? __switch_to_asm+0x34/0x70
[91349.972999] ? __switch_to_asm+0x40/0x70
[91349.973002] ? __switch_to_asm+0x34/0x70
[91349.973004] ? __switch_to_asm+0x40/0x70
[91349.973007] ? __switch_to_asm+0x34/0x70
[91349.973009] ? __switch_to_asm+0x40/0x70
[91349.973012] ? __switch_to_asm+0x34/0x70
[91349.973033] smb2_reconnect_server+0x190/0x2d0 [cifs]
[91349.973039] process_one_work+0x1fd/0x3f0
[91349.973043] worker_thread+0x34/0x410
[91349.973046] kthread+0x121/0x140
[91349.973050] ? process_one_work+0x3f0/0x3f0
[91349.973053] ? kthread_create_worker_on_cpu+0x70/0x70
[91349.973056] ret_from_fork+0x35/0x40
[91349.973059] INFO: task bash:11900 blocked for more than 120 seconds.
[91349.973062] Not tainted 4.18.0-18-generic #19~18.04.1-Ubuntu
[91349.973064] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

Mount options are put in a script run by sudo:
/bin/mount -t cifs -o user="${PLAIN_USER}",cruid="${DOMAIN_USERNAME}",domain="${PLAIN_DOMAIN}",sec=krb5,gid="${SUDO_GID}",uid="${SUDO_UID}",rw,noserverino,vers=2.1 //SERVER.DOMAIN.LOCAL/share "${USERS_HOME}/share"