I hibernate both the server and the client without doing any cleaning ( unmounting ) and when I bring them back, the client sometimes throws the error below. I won't be able to use the client until I restart the machine. Though this is happening on the latest rc1, I've witnessed this behaviour on the v5.1 series and previous ones as well. Regards, PECastro How to reproduce: Hibernate both client and server and bring them back. Kernel version: 5.2.0-rc1 OS: Fedora28 cifs package: cifs-utils-6.8-1.fc28.x86_64 <dmesg> [80492.738361] ====================================================== [80492.738364] WARNING: possible circular locking dependency detected [80492.738367] 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 Not tainted [80492.738370] ------------------------------------------------------ [80492.738373] cifsd/32288 is trying to acquire lock: [80492.738376] 000000007d281247 (&type->s_umount_key#63){++++}, at: iterate_supers_type+0x5e/0xd0 [80492.738386] but task is already holding lock: [80492.738388] 00000000ed20100a (&(&GlobalMid_Lock)->rlock){+.+.}, at: cifs_reconnect+0x4d/0x750 [cifs] [80492.738417] which lock already depends on the new lock. [80492.738420] the existing dependency chain (in reverse order) is: [80492.738424] -> #1 (&(&GlobalMid_Lock)->rlock){+.+.}: [80492.738433] lock_acquire+0x90/0x180 [80492.738439] _raw_spin_lock+0x2c/0x40 [80492.738451] _get_xid+0x12/0x50 [cifs] [80492.738461] cifs_writepages+0x61/0xd00 [cifs] [80492.738464] do_writepages+0x41/0xd0 [80492.738468] __writeback_single_inode+0x54/0x650 [80492.738472] writeback_sb_inodes+0x1fc/0x550 [80492.738475] __writeback_inodes_wb+0x5d/0xb0 [80492.738480] wb_writeback+0x340/0x4b0 [80492.738483] wb_workfn+0x43b/0x5c0 [80492.738488] process_one_work+0x2a5/0x660 [80492.738491] worker_thread+0x2d/0x3d0 [80492.738494] kthread+0x113/0x130 [80492.738497] ret_from_fork+0x3a/0x50 [80492.738500] -> #0 (&type->s_umount_key#63){++++}: [80492.738504] __lock_acquire+0xa18/0xe10 [80492.738507] lock_acquire+0x90/0x180 [80492.738510] down_read+0x28/0xc0 [80492.738516] iterate_supers_type+0x5e/0xd0 [80492.738524] cifs_reconnect+0x80/0x750 [cifs] [80492.738533] cifs_readv_from_socket+0x137/0x1d0 [cifs] [80492.738541] cifs_read_from_socket+0x4a/0x70 [cifs] [80492.738549] cifs_demultiplex_thread+0xed/0x820 [cifs] [80492.738553] kthread+0x113/0x130 [80492.738555] ret_from_fork+0x3a/0x50 [80492.738558] other info that might help us debug this: [80492.738560] Possible unsafe locking scenario: [80492.738562] CPU0 CPU1 [80492.738564] ---- ---- [80492.738566] lock(&(&GlobalMid_Lock)->rlock); [80492.738568] lock(&type->s_umount_key#63); [80492.738571] lock(&(&GlobalMid_Lock)->rlock); [80492.738574] lock(&type->s_umount_key#63); [80492.738576] *** DEADLOCK *** [80492.738579] 1 lock held by cifsd/32288: [80492.738581] #0: 00000000ed20100a (&(&GlobalMid_Lock)->rlock){+.+.}, at: cifs_reconnect+0x4d/0x750 [cifs] [80492.738591] stack backtrace: [80492.738595] CPU: 6 PID: 32288 Comm: cifsd Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80492.738598] Hardware name: LENOVO 20378/Lenovo Y50-70, BIOS 9ECN31WW(V1.14) 08/18/2014 [80492.738601] Call Trace: [80492.738607] dump_stack+0x67/0x90 [80492.738612] print_circular_bug.cold.60+0x15c/0x195 [80492.738616] check_prevs_add+0x766/0xea0 [80492.738622] ? find_held_lock+0x2d/0x90 [80492.738626] __lock_acquire+0xa18/0xe10 [80492.738630] lock_acquire+0x90/0x180 [80492.738634] ? iterate_supers_type+0x5e/0xd0 [80492.738644] ? allocate_buffers+0xa0/0xa0 [cifs] [80492.738649] down_read+0x28/0xc0 [80492.738653] ? iterate_supers_type+0x5e/0xd0 [80492.738656] iterate_supers_type+0x5e/0xd0 [80492.738665] cifs_reconnect+0x80/0x750 [cifs] [80492.738674] cifs_readv_from_socket+0x137/0x1d0 [cifs] [80492.738683] cifs_read_from_socket+0x4a/0x70 [cifs] [80492.738694] ? cifs_small_buf_get+0x16/0x20 [cifs] [80492.738703] cifs_demultiplex_thread+0xed/0x820 [cifs] [80492.738706] ? __kthread_parkme+0x4c/0x70 [80492.738715] ? cifs_handle_standard+0x180/0x180 [cifs] [80492.738725] ? cifs_handle_standard+0x180/0x180 [cifs] [80492.738728] kthread+0x113/0x130 [80492.738731] ? kthread_create_on_node+0x60/0x60 [80492.738734] ret_from_fork+0x3a/0x50 [80609.471622] INFO: task file.so:27701 blocked for more than 122 seconds. [80609.471632] Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80609.471635] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [80609.471638] file.so D13512 27701 3233 0x00000000 [80609.471645] Call Trace: [80609.471654] ? __schedule+0x310/0x770 [80609.471661] schedule+0x30/0xb0 [80609.471665] schedule_preempt_disabled+0x11/0x20 [80609.471669] __mutex_lock+0x448/0x8b0 [80609.471674] ? find_held_lock+0x2d/0x90 [80609.471699] ? open_shroot+0x76/0x450 [cifs] [80609.471727] ? open_shroot+0x76/0x450 [cifs] [80609.471744] open_shroot+0x76/0x450 [cifs] [80609.471756] ? find_held_lock+0x2d/0x90 [80609.471767] ? rcu_read_lock_sched_held+0x74/0x80 [80609.471775] ? __alloc_pages_nodemask+0x36c/0x3c0 [80609.471791] ? smb2_query_path_info+0x18a/0x320 [cifs] [80609.471808] smb2_query_path_info+0x18a/0x320 [cifs] [80609.471826] ? cifs_get_inode_info+0x1bf/0x6b0 [cifs] [80609.471833] ? rcu_read_lock_sched_held+0x74/0x80 [80609.471851] cifs_get_inode_info+0x1fa/0x6b0 [cifs] [80609.471867] ? build_path_from_dentry_optional_prefix+0x262/0x5c0 [cifs] [80609.471874] ? __kmalloc+0x283/0x2b0 [80609.471884] ? build_path_from_dentry_optional_prefix+0x27f/0x5c0 [cifs] [80609.471897] cifs_revalidate_dentry_attr+0xd1/0x3c0 [cifs] [80609.471909] cifs_getattr+0x63/0x1d0 [cifs] [80609.471915] vfs_statx+0x89/0xe0 [80609.471921] __do_sys_newlstat+0x39/0x70 [80609.471929] do_syscall_64+0x50/0x1b0 [80609.471935] entry_SYSCALL_64_after_hwframe+0x49/0xbe [80609.472014] RIP: 0033:0x7f72e3f454f5 [80609.472021] Code: Bad RIP value. [80609.472025] RSP: 002b:00007ffda0d33108 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 [80609.472029] RAX: ffffffffffffffda RBX: 000055a6c7372050 RCX: 00007f72e3f454f5 [80609.472032] RDX: 00007ffda0d33150 RSI: 00007ffda0d33150 RDI: 000055a6c7371050 [80609.472035] RBP: 00007ffda0d33220 R08: 000055a6c7371040 R09: 0000000000000001 [80609.472038] R10: 000055a6c737101d R11: 0000000000000246 R12: 000055a6c7371050 [80609.472042] R13: 000055a6c7371025 R14: 000055a6c7371024 R15: 000055a6c737105d [80609.472050] INFO: task file.so:27763 blocked for more than 122 seconds. [80609.472054] Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80609.472056] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [80609.472060] file.so D13944 27763 3233 0x00000000 [80609.472065] Call Trace: [80609.472071] ? __schedule+0x310/0x770 [80609.472077] schedule+0x30/0xb0 [80609.472081] schedule_preempt_disabled+0x11/0x20 [80609.472084] __mutex_lock+0x448/0x8b0 [80609.472089] ? find_held_lock+0x2d/0x90 [80609.472100] ? open_shroot+0x76/0x450 [cifs] [80609.472114] ? open_shroot+0x76/0x450 [cifs] [80609.472125] open_shroot+0x76/0x450 [cifs] [80609.472132] ? find_held_lock+0x2d/0x90 [80609.472139] ? rcu_read_lock_sched_held+0x74/0x80 [80609.472143] ? __alloc_pages_nodemask+0x36c/0x3c0 [80609.472158] ? smb2_query_path_info+0x18a/0x320 [cifs] [80609.472169] smb2_query_path_info+0x18a/0x320 [cifs] [80609.472180] ? cifs_get_inode_info+0x1bf/0x6b0 [cifs] [80609.472185] ? rcu_read_lock_sched_held+0x74/0x80 [80609.472196] cifs_get_inode_info+0x1fa/0x6b0 [cifs] [80609.472207] ? build_path_from_dentry_optional_prefix+0x262/0x5c0 [cifs] [80609.472212] ? __kmalloc+0x283/0x2b0 [80609.472223] ? build_path_from_dentry_optional_prefix+0x27f/0x5c0 [cifs] [80609.472235] cifs_revalidate_dentry_attr+0xd1/0x3c0 [cifs] [80609.472246] cifs_getattr+0x63/0x1d0 [cifs] [80609.472252] vfs_statx+0x89/0xe0 [80609.472257] __do_sys_newlstat+0x39/0x70 [80609.472265] do_syscall_64+0x50/0x1b0 [80609.472270] entry_SYSCALL_64_after_hwframe+0x49/0xbe [80609.472273] RIP: 0033:0x7f72e3f454f5 [80609.472278] Code: Bad RIP value. [80609.472281] RSP: 002b:00007ffda0d33108 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 [80609.472285] RAX: ffffffffffffffda RBX: 000055a6c7372050 RCX: 00007f72e3f454f5 [80609.472288] RDX: 00007ffda0d33150 RSI: 00007ffda0d33150 RDI: 000055a6c7371050 [80609.472291] RBP: 00007ffda0d33220 R08: 000055a6c7371040 R09: 0000000000000001 [80609.472294] R10: 000055a6c737101d R11: 0000000000000246 R12: 000055a6c7371050 [80609.472297] R13: 000055a6c7371025 R14: 000055a6c7371024 R15: 000055a6c737105d [80609.472305] INFO: task file.so:27809 blocked for more than 122 seconds. [80609.472399] Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80609.472402] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [80609.472405] file.so D14200 27809 3233 0x00000000 [80609.472411] Call Trace: [80609.472416] ? __schedule+0x310/0x770 [80609.472421] schedule+0x30/0xb0 [80609.472425] schedule_preempt_disabled+0x11/0x20 [80609.472429] __mutex_lock+0x448/0x8b0 [80609.472433] ? find_held_lock+0x2d/0x90 [80609.472445] ? open_shroot+0x76/0x450 [cifs] [80609.472458] ? open_shroot+0x76/0x450 [cifs] [80609.472479] open_shroot+0x76/0x450 [cifs] [80609.472485] ? find_held_lock+0x2d/0x90 [80609.472490] ? rcu_read_lock_sched_held+0x74/0x80 [80609.472493] ? __alloc_pages_nodemask+0x36c/0x3c0 [80609.472504] ? smb2_query_path_info+0x18a/0x320 [cifs] [80609.472513] smb2_query_path_info+0x18a/0x320 [cifs] [80609.472521] ? cifs_get_inode_info+0x1bf/0x6b0 [cifs] [80609.472525] ? rcu_read_lock_sched_held+0x74/0x80 [80609.472533] cifs_get_inode_info+0x1fa/0x6b0 [cifs] [80609.472542] ? build_path_from_dentry_optional_prefix+0x262/0x5c0 [cifs] [80609.472545] ? __kmalloc+0x283/0x2b0 [80609.472553] ? build_path_from_dentry_optional_prefix+0x27f/0x5c0 [cifs] [80609.472566] cifs_revalidate_dentry_attr+0xd1/0x3c0 [cifs] [80609.472575] cifs_getattr+0x63/0x1d0 [cifs] [80609.472580] vfs_statx+0x89/0xe0 [80609.472585] __do_sys_newlstat+0x39/0x70 [80609.472591] do_syscall_64+0x50/0x1b0 [80609.472595] entry_SYSCALL_64_after_hwframe+0x49/0xbe [80609.472598] RIP: 0033:0x7f72e3f454f5 [80609.472603] Code: Bad RIP value. [80609.472605] RSP: 002b:00007ffda0d33108 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 [80609.472608] RAX: ffffffffffffffda RBX: 000055a6c7372050 RCX: 00007f72e3f454f5 [80609.472611] RDX: 00007ffda0d33150 RSI: 00007ffda0d33150 RDI: 000055a6c7371050 [80609.472614] RBP: 00007ffda0d33220 R08: 000055a6c7371040 R09: 0000000000000001 [80609.472617] R10: 000055a6c737101d R11: 0000000000000246 R12: 000055a6c7371050 [80609.472620] R13: 000055a6c7371025 R14: 000055a6c7371024 R15: 000055a6c737105d [80609.472627] INFO: lockdep is turned off. [80732.350522] INFO: task file.so:9608 blocked for more than 122 seconds. [80732.350539] Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80732.350543] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [80732.350546] file.so D11704 9608 3233 0x00004000 [80732.350552] Call Trace: [80732.350562] ? __schedule+0x310/0x770 [80732.350568] ? __mutex_lock+0xcb/0x8b0 [80732.350574] schedule+0x30/0xb0 [80732.350578] schedule_preempt_disabled+0x11/0x20 [80732.350581] __mutex_lock+0x448/0x8b0 [80732.350587] ? find_nls+0x16/0x80 [80732.350606] ? smb2_reconnect.part.23+0x1c9/0x5a0 [cifs] [80732.350623] ? smb2_reconnect.part.23+0x1c9/0x5a0 [cifs] [80732.350634] smb2_reconnect.part.23+0x1c9/0x5a0 [cifs] [80732.350641] ? wait_woken+0x80/0x80 [80732.350653] smb2_plain_req_init+0x4b/0x290 [cifs] [80732.350659] ? _raw_spin_unlock+0x24/0x40 [80732.350669] SMB2_open_init+0x6c/0x700 [cifs] [80732.350683] open_shroot+0x174/0x450 [cifs] [80732.350702] ? smb2_query_path_info+0x18a/0x320 [cifs] [80732.350712] smb2_query_path_info+0x18a/0x320 [cifs] [80732.350722] ? cifs_get_inode_info+0x1bf/0x6b0 [cifs] [80732.350727] ? rcu_read_lock_sched_held+0x74/0x80 [80732.350737] cifs_get_inode_info+0x1fa/0x6b0 [cifs] [80732.350746] ? build_path_from_dentry_optional_prefix+0x262/0x5c0 [cifs] [80732.350751] ? __kmalloc+0x283/0x2b0 [80732.350762] ? build_path_from_dentry_optional_prefix+0x27f/0x5c0 [cifs] [80732.350772] cifs_revalidate_dentry_attr+0xd1/0x3c0 [cifs] [80732.350782] cifs_getattr+0x63/0x1d0 [cifs] [80732.350787] vfs_statx+0x89/0xe0 [80732.350792] __do_sys_newlstat+0x39/0x70 [80732.350799] do_syscall_64+0x50/0x1b0 [80732.350803] entry_SYSCALL_64_after_hwframe+0x49/0xbe [80732.350807] RIP: 0033:0x7f72e3f454f5 [80732.350813] Code: Bad RIP value. [80732.350817] RSP: 002b:00007ffda0d33108 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 [80732.350820] RAX: ffffffffffffffda RBX: 000055a6c73850e0 RCX: 00007f72e3f454f5 [80732.350823] RDX: 00007ffda0d33150 RSI: 00007ffda0d33150 RDI: 000055a6c73840e0 [80732.350825] RBP: 00007ffda0d33220 R08: 0000000000000003 R09: 0000000000000000 [80732.350828] R10: 000055a6c73840ad R11: 0000000000000246 R12: 000055a6c73840e0 [80732.350831] R13: 000055a6c73840b5 R14: 000055a6c73840b4 R15: 000055a6c73840ed [80732.350842] INFO: task kworker/6:2:1159 blocked for more than 122 seconds. [80732.350845] Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80732.350848] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [80732.350850] kworker/6:2 D11096 1159 2 0x80004000 [80732.350864] Workqueue: cifsiod smb2_reconnect_server [cifs] [80732.350866] Call Trace: [80732.350871] ? __schedule+0x310/0x770 [80732.350876] schedule+0x30/0xb0 [80732.350879] schedule_preempt_disabled+0x11/0x20 [80732.350882] __mutex_lock+0x448/0x8b0 [80732.350890] ? cifs_mark_open_files_invalid+0x56/0x80 [cifs] [80732.350900] ? cifs_mark_open_files_invalid+0x56/0x80 [cifs] [80732.350906] cifs_mark_open_files_invalid+0x56/0x80 [cifs] [80732.350916] smb2_reconnect.part.23+0x20f/0x5a0 [cifs] [80732.350922] ? _raw_spin_lock+0x2c/0x40 [80732.350932] smb2_reconnect_server+0x142/0x200 [cifs] [80732.350939] process_one_work+0x2a5/0x660 [80732.350944] ? process_one_work+0x660/0x660 [80732.350948] worker_thread+0x2d/0x3d0 [80732.350952] ? process_one_work+0x660/0x660 [80732.350955] kthread+0x113/0x130 [80732.350958] ? kthread_create_on_node+0x60/0x60 [80732.350962] ret_from_fork+0x3a/0x50 [80732.350973] INFO: task sadc:27559 blocked for more than 122 seconds. [80732.350976] Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80732.350978] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [80732.350981] sadc D11184 27559 1 0x00000000 [80732.350985] Call Trace: [80732.350990] ? __schedule+0x310/0x770 [80732.350993] ? __mutex_lock+0xcb/0x8b0 [80732.350997] schedule+0x30/0xb0 [80732.351000] schedule_preempt_disabled+0x11/0x20 [80732.351003] __mutex_lock+0x448/0x8b0 [80732.351007] ? find_nls+0x16/0x80 [80732.351027] ? smb2_reconnect.part.23+0x1c9/0x5a0 [cifs] [80732.351038] ? smb2_reconnect.part.23+0x1c9/0x5a0 [cifs] [80732.351046] smb2_reconnect.part.23+0x1c9/0x5a0 [cifs] [80732.351061] smb2_plain_req_init+0x4b/0x290 [cifs] [80732.351073] SMB2_open_init+0x6c/0x700 [cifs] [80732.351083] ? cifs_small_buf_release.part.10+0x11/0x20 [cifs] [80732.351087] ? kmem_cache_free+0x130/0x2c0 [80732.351097] smb2_query_info_compound+0x180/0x3a0 [cifs] [80732.351104] ? lookup_fast+0xc8/0x430 [80732.351110] ? lockref_get_not_dead+0xc/0x30 [80732.351113] ? lookup_fast+0xc8/0x430 [80732.351128] ? smb2_queryfs+0x70/0xf0 [cifs] [80732.351138] smb2_queryfs+0x70/0xf0 [cifs] [80732.351147] cifs_statfs+0xb4/0x370 [cifs] [80732.351152] statfs_by_dentry+0x52/0x70 [80732.351155] vfs_statfs+0x16/0xc0 [80732.351159] user_statfs+0x54/0xa0 [80732.351163] __do_sys_statfs+0x20/0x50 [80732.351168] do_syscall_64+0x50/0x1b0 [80732.351172] entry_SYSCALL_64_after_hwframe+0x49/0xbe [80732.351175] RIP: 0033:0x7febb87c6657 [80732.351179] Code: Bad RIP value. [80732.351181] RSP: 002b:00007fff19fb1208 EFLAGS: 00000246 ORIG_RAX: 0000000000000089 [80732.351185] RAX: ffffffffffffffda RBX: 00007fff19fb13b0 RCX: 00007febb87c6657 [80732.351188] RDX: 0000000000000008 RSI: 00007fff19fb1210 RDI: 00007fff19fb13b0 [80732.351190] RBP: 00007fff19fb1210 R08: 0000000000000000 R09: 00007fff19fb13b5 [80732.351192] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff19fb12c0 [80732.351194] R13: 00007fff19fb13b0 R14: 0000000000000009 R15: 0000000000000000 [80732.351200] INFO: task file.so:27578 blocked for more than 122 seconds. [80732.351203] Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80732.351205] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [80732.351207] file.so D12488 27578 3233 0x00004000 [80732.351212] Call Trace: [80732.351216] ? __schedule+0x310/0x770 [80732.351218] ? __mutex_lock+0x4a0/0x8b0 [80732.351222] schedule+0x30/0xb0 [80732.351225] schedule_preempt_disabled+0x11/0x20 [80732.351228] __mutex_lock+0x448/0x8b0 [80732.351232] ? find_nls+0x16/0x80 [80732.351241] ? smb2_reconnect.part.23+0x1c9/0x5a0 [cifs] [80732.351252] ? smb2_reconnect.part.23+0x1c9/0x5a0 [cifs] [80732.351270] smb2_reconnect.part.23+0x1c9/0x5a0 [cifs] [80732.351285] ? wait_woken+0x80/0x80 [80732.351294] smb2_plain_req_init+0x4b/0x290 [cifs] [80732.351305] ? cifs_small_buf_release.part.10+0x11/0x20 [cifs] [80732.351316] SMB2_open_init+0x6c/0x700 [cifs] [80732.351328] smb2_query_info_compound+0x180/0x3a0 [cifs] [80732.351362] ? lookup_fast+0xc8/0x430 [80732.351381] ? lockref_get_not_dead+0xc/0x30 [80732.351386] ? lookup_fast+0xc8/0x430 [80732.351416] ? smb2_queryfs+0x70/0xf0 [cifs] [80732.351436] smb2_queryfs+0x70/0xf0 [cifs] [80732.351458] cifs_statfs+0xb4/0x370 [cifs] [80732.351463] statfs_by_dentry+0x52/0x70 [80732.351468] vfs_statfs+0x16/0xc0 [80732.351472] user_statfs+0x54/0xa0 [80732.351479] __do_sys_statfs+0x20/0x50 [80732.351487] do_syscall_64+0x50/0x1b0 [80732.351492] entry_SYSCALL_64_after_hwframe+0x49/0xbe [80732.351496] RIP: 0033:0x7f72e3f45657 [80732.351500] Code: Bad RIP value. [80732.351504] RSP: 002b:00007ffda0d33318 EFLAGS: 00000246 ORIG_RAX: 0000000000000089 [80732.351507] RAX: ffffffffffffffda RBX: 000055a6c736fed8 RCX: 00007f72e3f45657 [80732.351510] RDX: 0000000000000000 RSI: 00007ffda0d33320 RDI: 000055a6c736fed8 [80732.351513] RBP: 00007ffda0d33320 R08: 00007f72e4213c40 R09: 0000000000000026 [80732.351517] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffda0d333e0 [80732.351520] R13: 00007ffda0d333d8 R14: 000055a6c7348c68 R15: 000055a6c7367c80 [80732.351529] INFO: task file.so:27701 blocked for more than 245 seconds. [80732.351543] Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80732.351546] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [80732.351549] file.so D13512 27701 3233 0x00000000 [80732.351556] Call Trace: [80732.351562] ? __schedule+0x310/0x770 [80732.351568] schedule+0x30/0xb0 [80732.351582] schedule_preempt_disabled+0x11/0x20 [80732.351589] __mutex_lock+0x448/0x8b0 [80732.351594] ? find_held_lock+0x2d/0x90 [80732.351608] ? open_shroot+0x76/0x450 [cifs] [80732.351631] ? open_shroot+0x76/0x450 [cifs] [80732.351653] open_shroot+0x76/0x450 [cifs] [80732.351662] ? find_held_lock+0x2d/0x90 [80732.351670] ? rcu_read_lock_sched_held+0x74/0x80 [80732.351676] ? __alloc_pages_nodemask+0x36c/0x3c0 [80732.351693] ? smb2_query_path_info+0x18a/0x320 [cifs] [80732.351715] smb2_query_path_info+0x18a/0x320 [cifs] [80732.351739] ? cifs_get_inode_info+0x1bf/0x6b0 [cifs] [80732.351744] ? rcu_read_lock_sched_held+0x74/0x80 [80732.351757] cifs_get_inode_info+0x1fa/0x6b0 [cifs] [80732.351780] ? build_path_from_dentry_optional_prefix+0x262/0x5c0 [cifs] [80732.351796] ? __kmalloc+0x283/0x2b0 [80732.351809] ? build_path_from_dentry_optional_prefix+0x27f/0x5c0 [cifs] [80732.351824] cifs_revalidate_dentry_attr+0xd1/0x3c0 [cifs] [80732.351848] cifs_getattr+0x63/0x1d0 [cifs] [80732.351855] vfs_statx+0x89/0xe0 [80732.351878] __do_sys_newlstat+0x39/0x70 [80732.351897] do_syscall_64+0x50/0x1b0 [80732.351903] entry_SYSCALL_64_after_hwframe+0x49/0xbe [80732.351907] RIP: 0033:0x7f72e3f454f5 [80732.351913] Code: Bad RIP value. [80732.351916] RSP: 002b:00007ffda0d33108 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 [80732.351920] RAX: ffffffffffffffda RBX: 000055a6c7372050 RCX: 00007f72e3f454f5 [80732.351924] RDX: 00007ffda0d33150 RSI: 00007ffda0d33150 RDI: 000055a6c7371050 [80732.351928] RBP: 00007ffda0d33220 R08: 000055a6c7371040 R09: 0000000000000001 [80732.351933] R10: 000055a6c737101d R11: 0000000000000246 R12: 000055a6c7371050 [80732.351937] R13: 000055a6c7371025 R14: 000055a6c7371024 R15: 000055a6c737105d [80732.351947] INFO: task file.so:27763 blocked for more than 245 seconds. [80732.351951] Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80732.351955] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [80732.351959] file.so D13944 27763 3233 0x00000000 [80732.351975] Call Trace: [80732.351991] ? __schedule+0x310/0x770 [80732.352003] schedule+0x30/0xb0 [80732.352008] schedule_preempt_disabled+0x11/0x20 [80732.352012] __mutex_lock+0x448/0x8b0 [80732.352017] ? find_held_lock+0x2d/0x90 [80732.352031] ? open_shroot+0x76/0x450 [cifs] [80732.352067] ? open_shroot+0x76/0x450 [cifs] [80732.352081] open_shroot+0x76/0x450 [cifs] [80732.352090] ? find_held_lock+0x2d/0x90 [80732.352098] ? rcu_read_lock_sched_held+0x74/0x80 [80732.352104] ? __alloc_pages_nodemask+0x36c/0x3c0 [80732.352121] ? smb2_query_path_info+0x18a/0x320 [cifs] [80732.352135] smb2_query_path_info+0x18a/0x320 [cifs] [80732.352159] ? cifs_get_inode_info+0x1bf/0x6b0 [cifs] [80732.352175] ? rcu_read_lock_sched_held+0x74/0x80 [80732.352187] cifs_get_inode_info+0x1fa/0x6b0 [cifs] [80732.352201] ? build_path_from_dentry_optional_prefix+0x262/0x5c0 [cifs] [80732.352208] ? __kmalloc+0x283/0x2b0 [80732.352221] ? build_path_from_dentry_optional_prefix+0x27f/0x5c0 [cifs] [80732.352236] cifs_revalidate_dentry_attr+0xd1/0x3c0 [cifs] [80732.352250] cifs_getattr+0x63/0x1d0 [cifs] [80732.352258] vfs_statx+0x89/0xe0 [80732.352264] __do_sys_newlstat+0x39/0x70 [80732.352274] do_syscall_64+0x50/0x1b0 [80732.352280] entry_SYSCALL_64_after_hwframe+0x49/0xbe [80732.352284] RIP: 0033:0x7f72e3f454f5 [80732.352290] Code: Bad RIP value. [80732.352294] RSP: 002b:00007ffda0d33108 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 [80732.352298] RAX: ffffffffffffffda RBX: 000055a6c7372050 RCX: 00007f72e3f454f5 [80732.352369] RDX: 00007ffda0d33150 RSI: 00007ffda0d33150 RDI: 000055a6c7371050 [80732.352373] RBP: 00007ffda0d33220 R08: 000055a6c7371040 R09: 0000000000000001 [80732.352377] R10: 000055a6c737101d R11: 0000000000000246 R12: 000055a6c7371050 [80732.352380] R13: 000055a6c7371025 R14: 000055a6c7371024 R15: 000055a6c737105d [80732.352391] INFO: task file.so:27809 blocked for more than 245 seconds. [80732.352395] Not tainted 5.2.0-rc1.1.PEC40-00198-g4c4364477e1d #1 [80732.352398] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [80732.352401] file.so D14200 27809 3233 0x00000000 [80732.352411] Call Trace: [80732.352417] ? __schedule+0x310/0x770 [80732.352424] schedule+0x30/0xb0 [80732.352429] schedule_preempt_disabled+0x11/0x20 [80732.352433] __mutex_lock+0x448/0x8b0 [80732.352438] ? find_held_lock+0x2d/0x90 [80732.352451] ? open_shroot+0x76/0x450 [cifs] [80732.352468] ? open_shroot+0x76/0x450 [cifs] [80732.352481] open_shroot+0x76/0x450 [cifs] [80732.352490] ? find_held_lock+0x2d/0x90 [80732.352499] ? rcu_read_lock_sched_held+0x74/0x80 [80732.352504] ? __alloc_pages_nodemask+0x36c/0x3c0 [80732.352522] ? smb2_query_path_info+0x18a/0x320 [cifs] [80732.352536] smb2_query_path_info+0x18a/0x320 [cifs] [80732.352560] ? cifs_get_inode_info+0x1bf/0x6b0 [cifs] [80732.352566] ? rcu_read_lock_sched_held+0x74/0x80 [80732.352579] cifs_get_inode_info+0x1fa/0x6b0 [cifs] [80732.352602] ? build_path_from_dentry_optional_prefix+0x262/0x5c0 [cifs] [80732.352609] ? __kmalloc+0x283/0x2b0 [80732.352631] ? build_path_from_dentry_optional_prefix+0x27f/0x5c0 [cifs] [80732.352646] cifs_revalidate_dentry_attr+0xd1/0x3c0 [cifs] [80732.352660] cifs_getattr+0x63/0x1d0 [cifs] [80732.352666] vfs_statx+0x89/0xe0 [80732.352673] __do_sys_newlstat+0x39/0x70 [80732.352682] do_syscall_64+0x50/0x1b0 [80732.352689] entry_SYSCALL_64_after_hwframe+0x49/0xbe [80732.352693] RIP: 0033:0x7f72e3f454f5 [80732.352698] Code: Bad RIP value. [80732.352702] RSP: 002b:00007ffda0d33108 EFLAGS: 00000246 ORIG_RAX: 0000000000000006 [80732.352706] RAX: ffffffffffffffda RBX: 000055a6c7372050 RCX: 00007f72e3f454f5 [80732.352711] RDX: 00007ffda0d33150 RSI: 00007ffda0d33150 RDI: 000055a6c7371050 [80732.352715] RBP: 00007ffda0d33220 R08: 000055a6c7371040 R09: 0000000000000001 [80732.352719] R10: 000055a6c737101d R11: 0000000000000246 R12: 000055a6c7371050 [80732.352722] R13: 000055a6c7371025 R14: 000055a6c7371024 R15: 000055a6c737105d [80732.352732] INFO: lockdep is turned off. </dmesg>
This is still the case for me with Samba v4.10.6 on server and v5.2.6 kernel on the client. Once I restart server with mountpoints being mounted on the client and not unmounted prior to restart, the mountpoints stall, and the client tasks stuck with the following stack trace: === srp 04 13:47:52 spock kernel: dolphin D 0 1039 873 0x00000080 srp 04 13:47:52 spock kernel: Call Trace: srp 04 13:47:52 spock kernel: schedule+0x8c/0x250 srp 04 13:47:52 spock kernel: schedule_preempt_disabled+0x6c/0x140 srp 04 13:47:52 spock kernel: __mutex_lock.isra.0+0x28d/0x540 srp 04 13:47:52 spock kernel: open_shroot+0xf5/0x640 [cifs] srp 04 13:47:52 spock kernel: smb2_query_path_info+0x19d/0x330 [cifs] srp 04 13:47:52 spock kernel: cifs_get_inode_info+0x3c8/0xa70 [cifs] srp 04 13:47:52 spock kernel: cifs_revalidate_dentry_attr+0x12d/0x3f0 [cifs] srp 04 13:47:52 spock kernel: cifs_getattr+0x5b/0x190 [cifs] srp 04 13:47:52 spock kernel: __se_sys_newlstat+0x8e/0x100 srp 04 13:47:52 spock kernel: do_syscall_64+0x5f/0x1d0 srp 04 13:47:52 spock kernel: entry_SYSCALL_64_after_hwframe+0x44/0xa9 ===
Fixed in 5.4 kernel (and later) and was backported to stable for 5.3.4, 5.2.18 etc) See patch https://patchwork.kernel.org/patch/11143873/