When I close the lid of my Acer Nitro laptop, I see this in my journal:
systemd-logind[628]: Lid closed.
systemd-logind[628]: Suspending...
...
systemd-sleep[2396]: Entering sleep state 'suspend'...
kernel: PM: suspend entry (deep)
kernel: Filesystems sync: 0.004 seconds
kernel: Freezing user space processes
kernel: Freezing user space processes failed after 20.002 seconds (1 tasks refusing to freeze, wq_busy=0):
kernel: task:(sd-bright) state:D stack:0 pid:2229 ppid:628 flags:0x00000006
kernel: Call Trace:
kernel: <TASK>
kernel: __schedule+0x2aa/0x610
kernel: schedule+0x63/0x110
kernel: schedule_preempt_disabled+0x15/0x30
kernel: __mutex_lock.constprop.0+0x3f8/0x7a0
kernel: __mutex_lock_slowpath+0x13/0x20
kernel: mutex_lock+0x3c/0x50
kernel: backlight_device_set_brightness+0x35/0x140
kernel: brightness_store+0x75/0x90
kernel: dev_attr_store+0x17/0x40
kernel: sysfs_kf_write+0x3e/0x60
kernel: kernfs_fop_write_iter+0x133/0x210
kernel: vfs_write+0x251/0x410
kernel: ksys_write+0x73/0x100
kernel: __x64_sys_write+0x19/0x30
kernel: do_syscall_64+0x5b/0x90
kernel: ? __x64_sys_fcntl+0xba/0xe0
kernel: ? exit_to_user_mode_prepare+0x30/0xb0
kernel: ? syscall_exit_to_user_mode+0x29/0x50
kernel: ? do_syscall_64+0x67/0x90
kernel: ? do_user_addr_fault+0x1bb/0x620
kernel: ? exit_to_user_mode_prepare+0x30/0xb0
kernel: ? irqentry_exit_to_user_mode+0x9/0x20
kernel: ? irqentry_exit+0x43/0x50
kernel: ? exc_page_fault+0x91/0x1b0
kernel: entry_SYSCALL_64_after_hwframe+0x72/0xdc
kernel: RIP: 0033:0x7f82d990ba1f
kernel: RSP: 002b:00007ffe7b9afc10 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
kernel: RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f82d990ba1f
kernel: RDX: 0000000000000004 RSI: 00007ffe7b9afcf0 RDI: 0000000000000004
kernel: RBP: 00007ffe7b9afcf0 R08: 0000000000000000 R09: 00007f82d99f6c80
kernel: R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000004
kernel: R13: 0000561cdb4a95b0 R14: 0000000000000004 R15: 00007f82d99f2d00
kernel: </TASK>
I cannot find sd-bright in the list from systemctl command.
Also dpkg -S sd-bright yields nothing.
OS: Ubuntu 23.04
kernel: 6.2.0-32-generic
