[Samba] task "smbd" blocked for more than x seconds (followed by call trace)

[Alex]

Hi,

I have a samba 4.15.13 file server running on Ubuntu 20.04.6, fully
updated/patched. The samba shared folders are stored on an XFS formatted
drive.
Intermittently, usually after 1 or 2 weeks of normal operation, browsing
the shared drive will freeze Windows Explorer, and when I look at the file
server console, I see the messages below over and over again:

[2955729.823684] INFO: task smbd:2888777 blocked for more than 120 seconds.
[2955729.824540]       Not tainted 5.4.0-172-generic #190-Ubuntu
[2955729.824989] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
disables this message.
[2955729.825549] smbd            D    0 2888777   1737 0x00000080
[2955729.825565] Call Trace:
[2955729.825674]  __schedule+0x2e3/0x740
[2955729.825689]  schedule+0x42/0xb0
[2955729.825698]  rwsem_down_read_slowpath+0x16c/0x4a0
[2955729.825760]  __down_read+0x6b/0x80
[2955729.825769]  __percpu_down_read+0x54/0x80
[2955729.825802]  __sb_start_write+0x79/0x80
[2955729.825848]  mnt_want_write+0x24/0x60
[2955729.825866]  do_last+0x8ea/0x900
[2955729.825877]  ? __alloc_file+0x94/0x110
[2955729.825890]  path_openat+0x8d/0x290
[2955729.825904]  do_filp_open+0x91/0x100
[2955729.825923]  ? __alloc_fd+0x46/0x150
[2955729.825954]  do_sys_open+0x17e/0x290
[2955729.825991]  ? __audit_syscall_exit+0x233/0x290
[2955729.826005]  __x64_sys_openat+0x20/0x30
[2955729.826036]  do_syscall_64+0x57/0x190
[2955729.826055]  entry_SYSCALL_64_after_hwframe+0x5c/0xc1
[2955729.826085] RIP: 0033:0x7fac5d210163
[2955729.826098] Code: Bad RIP value.
[2955729.826103] RSP: 002b:00007ffec466ae50 EFLAGS: 00000293 ORIG_RAX:
0000000000000101
[2955729.826119] RAX: ffffffffffffffda RBX: 0000555ed448f100 RCX:
00007fac5d210163
[2955729.826124] RDX: 00000000000208c2 RSI: 0000555ed441fd20 RDI:
00000000ffffff9c
[2955729.826128] RBP: 0000555ed441fd20 R08: 0000000000000000 R09:
00000000000001e4
[2955729.826133] R10: 00000000000001e4 R11: 0000000000000293 R12:
00000000000208c2
[2955729.826138] R13: 00000000000001e4 R14: 0000555ed43c7b40 R15:
0000555ed43c7b40
[2955850.658135] INFO: task smbd:2888777 blocked for more than 241 seconds.
[2955850.659195]       Not tainted 5.4.0-172-generic #190-Ubuntu
[2955850.659800] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
disables this message.
[2955850.660549] smbd            D    0 2888777   1737 0x00000080
[2955850.660560] Call Trace:
[2955850.660586]  __schedule+0x2e3/0x740
[2955850.660604]  schedule+0x42/0xb0
[2955850.660615]  rwsem_down_read_slowpath+0x16c/0x4a0
[2955850.660640]  __down_read+0x6b/0x80
[2955850.660651]  __percpu_down_read+0x54/0x80
[2955850.660665]  __sb_start_write+0x79/0x80
[2955850.660678]  mnt_want_write+0x24/0x60
[2955850.660690]  do_last+0x8ea/0x900
[2955850.660703]  ? __alloc_file+0x94/0x110
[2955850.660719]  path_openat+0x8d/0x290
[2955850.660736]  do_filp_open+0x91/0x100
[2955850.660756]  ? __alloc_fd+0x46/0x150
[2955850.660773]  do_sys_open+0x17e/0x290
[2955850.660785]  ? __audit_syscall_exit+0x233/0x290
[2955850.660802]  __x64_sys_openat+0x20/0x30
[2955850.660814]  do_syscall_64+0x57/0x190
[2955850.660827]  entry_SYSCALL_64_after_hwframe+0x5c/0xc1
[2955850.660836] RIP: 0033:0x7fac5d210163
[2955850.660845] Code: 89 7c 24 18 44 89 54 24 0c e8 99 64 f8 ff 44 8b 54
24 0c 8b 54 24 1c 41 89 c0 48 8b 74 24 10 8b 7c 24 18 b8 01 01 00 00 0f 05
<48> 3d 00 f0 ff ff 77 2b 44 89 c7 89 44 24 0c e8 c9 64 f8 ff 8b 44
[2955850.660851] RSP: 002b:00007ffec466ae50 EFLAGS: 00000293 ORIG_RAX:
0000000000000101
[2955850.660861] RAX: ffffffffffffffda RBX: 0000555ed448f100 RCX:
00007fac5d210163
[2955850.660867] RDX: 00000000000208c2 RSI: 0000555ed441fd20 RDI:
00000000ffffff9c
[2955850.660873] RBP: 0000555ed441fd20 R08: 0000000000000000 R09:
00000000000001e4
[2955850.660879] R10: 00000000000001e4 R11: 0000000000000293 R12:
00000000000208c2
[2955850.660885] R13: 00000000000001e4 R14: 0000555ed43c7b40 R15:
0000555ed43c7b40
[2955971.492313] INFO: task smbd:2888777 blocked for more than 362 seconds.
[2955971.493227]       Not tainted 5.4.0-172-generic #190-Ubuntu
[2955971.493694] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
disables this message.
[2955971.494231] smbd            D    0 2888777   1737 0x00000080
[2955971.494253] Call Trace:
[2955971.494592]  __schedule+0x2e3/0x740
[2955971.494609]  schedule+0x42/0xb0
[2955971.494618]  rwsem_down_read_slowpath+0x16c/0x4a0
[2955971.494637]  __down_read+0x6b/0x80
[2955971.494645]  __percpu_down_read+0x54/0x80
[2955971.494656]  __sb_start_write+0x79/0x80
[2955971.494666]  mnt_want_write+0x24/0x60



systemctl restart smbd hangs.
Rebooting the server solves the issue, until in eventually occurs again a
week or two later.

Any advice on troubleshooting this?

Thanks!

Peter