This project helps to develop and build Linux kernel modules in VSCode on an alien platform, primarily on Mac (and on Windows too). It uses Docker container with Linux environment and GCC compiler and VSCode's great feature "Remote - Containers" (need to install the same named plugin).
The project is based on Aleksandr Mezin's vscode-linux-kernel project and Asad Akbar's handy-kernel_modules project. Thank them a lot. The main differences from the former is work-in-docker ability, and from the latter is Qemu and Buildroot independency (no cross-compile).
- Install VSCode Remote - Containers plugin and corresponding Docker software. See the details here
- Clone this project
- to be continued
Simple kernel module
# insmod helloworld.ko
[ 8604.716927] Helloworld_module: init
#
# rmmod helloworld.ko
[ 8610.234228] Helloworld_module: exit
#
A kernel module which can accept parameters.
-
Insert module with no parameter
#
# insmod helloworld_param.ko
[ 8773.412883] Helloworld_module: init
[ 8773.413270] Helloworld_parameters:
[ 8773.413524] - param_integer # 500
[ 8773.413785] - param_array # [ 500][ 501][ 502]
[ 8773.414045] - param_string # helloworld
#
# rmmod helloworld_param.ko
[ 8780.668106] Helloworld_module: exit
[ 8780.668684] Helloworld_parameters:
[ 8780.668980] - param_integer # 500
[ 8780.669249] - param_array # [ 500][ 501][ 502]
[ 8780.669564] - param_string # helloworld
#
- Insert module with user defined parameter
# insmod helloworld_param.ko param_integer=600 param_string="testing" param_array=1,2,3
[ 8869.944889] Helloworld_module: init
[ 8869.945650] Helloworld_parameters:
[ 8869.945948] - param_integer # 600
[ 8869.949919] - param_array # [ 1][ 2][ 3]
[ 8869.952371] - param_string # testing
#
# rmmod helloworld_param.ko
[ 8893.422618] Helloworld_module: exit
[ 8893.423951] Helloworld_parameters:
[ 8893.424284] - param_integer # 600
[ 8893.424550] - param_array # [ 1][ 2][ 3]
[ 8893.424878] - param_string # testing
#
An example of how to use container_of.
# modinfo container_of.ko
filename: /root/container_of.ko
author: aakbar5 <[email protected]>
license: GPL
description: co: container_of example
version: 0.0.1
srcversion: 39B80B8E047FA102727B810
depends:
name: container_of
vermagic: 5.4.0-00001-gade746754348-dirty SMP preempt mod_unload aarch64
parm: param_count:Number of groups to be created -- (Read only) (int)
parm: param_idx:Index of the group to be shown -- (Read/write only) (int)
# insmod container_of.ko
[11503.238689] co: init
[11503.240342] Group @ index based
[11503.240556] - Id # 32
[11503.240742] - Obj1 # 21 -- obj1=1
[11503.240949] - Obj2 # 11 -- obj2=1
[11503.241165] Group @ container_of @ id
[11503.241349] - Id # 32
[11503.241517] - Obj1 # 21 -- obj1=1
[11503.241698] - Obj2 # 11 -- obj2=1
[11503.241893] Group @ container_of @ obj1
[11503.242079] - Id # 32
[11503.242246] - Obj1 # 21 -- obj1=1
[11503.242435] - Obj2 # 11 -- obj2=1
#
# rmmod container_of.ko
[11523.668908] co: exit
#
# insmod container_of.ko param_idx=2
[ 46.364041] container_of: loading out-of-tree module taints kernel.
[ 46.397061] co: init
[ 46.400697] Group @ index based
[ 46.400988] - Id # 34
[ 46.401183] - Obj1 # 22 -- obj1=2
[ 46.401410] - Obj2 # 12 -- obj2=2
[ 46.401628] Group @ container_of @ id
[ 46.406580] - Id # 34
[ 46.406878] - Obj1 # 22 -- obj1=2
[ 46.407131] - Obj2 # 12 -- obj2=2
[ 46.407360] Group @ container_of @ obj1
[ 46.407643] - Id # 34
[ 46.407889] - Obj1 # 22 -- obj1=2
[ 46.408230] - Obj2 # 12 -- obj2=2
An example of how to kernel linked list interface.
# insmod linked_list.ko
[ 796.369350] ll: init
[ 796.370399] Add nodes to the list...
[ 796.371385] List is not empty
[ 796.371567] Traverse the list...
[ 796.371774] #1: obj=0
[ 796.371944] #2: obj=1
[ 796.372098] #3: obj=2
[ 796.372249] #4: obj=3
[ 796.372400] #5: obj=4
[ 796.372554] Delete all nodes from the list...
[ 796.373165] List is empty
[ 796.373361] Traverse the list...
#
# rmmod linked_list.ko
[ 812.966234] ll: exit
#
An example of usage of for_each_process.
#
# insmod proc_info.ko
[37227.566385] proinfo_module: init
[37227.575743] PID NAME STATE TIME
[37227.576613] 1 init Stopped[In] 00:00:00
[37227.576974] 2 kthreadd Stopped[In] 00:00:00
[37227.577241] 3 rcu_gp Stopped[UnNo] 00:00:00
[37227.577522] 4 rcu_par_gp Stopped[UnNo] 00:00:00
[37227.577779] 6 kworker/0:0H Stopped[UnNo] 00:00:00
[37227.578037] 8 mm_percpu_wq Stopped[UnNo] 00:00:00
[37227.578319] 9 ksoftirqd/0 Stopped[In] 00:00:00
[37227.578587] 10 rcu_preempt Stopped[UnNo] 00:00:00
[37227.578865] 11 migration/0 Stopped[In] 00:00:00
[37227.579131] 12 cpuhp/0 Stopped[In] 00:00:00
[37227.579401] 13 cpuhp/1 Stopped[In] 00:00:00
[37227.579677] 14 migration/1 Stopped[In] 00:00:00
[37227.579971] 15 ksoftirqd/1 Stopped[In] 00:00:00
[37227.580296] 16 kworker/1:0 Stopped[UnNo] 00:00:00
[37227.580729] 17 kworker/1:0H Stopped[UnNo] 00:00:00
[37227.581011] 18 kdevtmpfs Stopped[In] 00:00:00
[37227.581280] 19 netns Stopped[UnNo] 00:00:00
[37227.581555] 20 rcu_tasks_kthre Stopped[In] 00:00:00
[37227.581847] 21 kworker/0:1 Stopped[UnNo] 00:00:00
[37227.582355] 22 kworker/1:1 Stopped[UnNo] 00:00:00
[37227.583305] 23 kauditd Stopped[In] 00:00:00
[37227.583620] 24 oom_reaper Stopped[In] 00:00:00
[37227.583998] 25 writeback Stopped[UnNo] 00:00:00
[37227.584653] 26 kcompactd0 Stopped[In] 00:00:00
[37227.584988] 27 ksmd Stopped[In] 00:00:00
[37227.585294] 28 khugepaged Stopped[In] 00:00:00
[37227.585603] 46 cryptd Stopped[UnNo] 00:00:00
[37227.585935] 77 kintegrityd Stopped[UnNo] 00:00:01
[37227.586283] 78 kblockd Stopped[UnNo] 00:00:01
[37227.586657] 79 blkcg_punt_bio Stopped[UnNo] 00:00:01
[37227.586986] 80 tpm_dev_wq Stopped[UnNo] 00:00:01
[37227.587359] 81 ata_sff Stopped[UnNo] 00:00:01
[37227.587705] 82 edac-poller Stopped[UnNo] 00:00:01
[37227.588303] 83 devfreq_wq Stopped[UnNo] 00:00:01
[37227.588645] 84 watchdogd Stopped[In] 00:00:01
[37227.588950] 85 rpciod Stopped[UnNo] 00:00:01
[37227.589260] 86 kworker/u5:0 Stopped[UnNo] 00:00:01
[37227.589598] 87 xprtiod Stopped[UnNo] 00:00:01
[37227.589930] 146 kswapd0 Stopped[In] 00:00:02
[37227.590287] 147 nfsiod Stopped[UnNo] 00:00:02
[37227.590615] 151 kworker/1:1H Stopped[UnNo] 00:00:04
[37227.590950] 152 vfio-irqfd-clea Stopped[UnNo] 00:00:04
[37227.591276] 153 jbd2/vda-8 Stopped[In] 00:00:05
[37227.591591] 154 ext4-rsv-conver Stopped[UnNo] 00:00:05
[37227.592152] 155 kworker/0:1H Stopped[UnNo] 00:00:05
[37227.592673] 170 syslogd Stopped[In] 00:00:08
[37227.593004] 174 klogd Stopped[In] 00:00:08
[37227.593326] 185 irqbalance Stopped[In] 00:00:09
[37227.593589] 199 dbus-daemon Stopped[In] 00:00:11
[37227.593881] 205 rpcbind Stopped[In] 00:00:11
[37227.594208] 239 dhcpcd Stopped[In] 00:00:15
[37227.594559] 245 dropbear Stopped[In] 00:00:16
[37227.594881] 259 rpc.statd Stopped[In] 00:00:20
[37227.595217] 275 rpc.mountd Stopped[In] 00:00:21
[37227.595503] 280 sh Stopped[In] 00:00:22
[37227.595901] 290 dropbear Stopped[In] 00:14:19
[37227.596589] 291 sh Stopped[In] 00:14:20
[37227.597007] 393 kworker/0:2 Stopped[UnNo] 01:41:33
[37227.597347] 594 kworker/u4:0 Stopped[UnNo] 09:54:22
[37227.597643] 599 kworker/u4:2 Stopped[UnNo] 10:07:30
[37227.598210] 615 insmod running 10:20:26
[37227.598819] Code Section: 0x0000000000400000 -- 0x0000000000418140
[37227.599265] Data Section: 0x0000000000428cb8 -- 0x0000000000429380
[37227.599595] Stack: 0x0000ffffca7d5ee0
[37227.600168] Task size: 0x1000000000000
[37227.600428] VMA Count: 21
[37227.600729] VMA # 1: 0x0000000000400000 -- 0x0000000000419000
[37227.601051] VMA # 2: 0x0000000000428000 -- 0x0000000000429000
[37227.601342] VMA # 3: 0x0000000000429000 -- 0x000000000042a000
[37227.601660] VMA # 4: 0x0000000017717000 -- 0x0000000017738000
[37227.601973] VMA # 5: 0x0000ffff8358e000 -- 0x0000ffff835c7000
[37227.602305] VMA # 6: 0x0000ffff835c7000 -- 0x0000ffff836f9000
[37227.602641] VMA # 7: 0x0000ffff836f9000 -- 0x0000ffff83709000
[37227.602948] VMA # 8: 0x0000ffff83709000 -- 0x0000ffff8370d000
[37227.603251] VMA # 9: 0x0000ffff8370d000 -- 0x0000ffff8370f000
[37227.603589] VMA # 10: 0x0000ffff8370f000 -- 0x0000ffff83713000
[37227.604284] VMA # 11: 0x0000ffff83713000 -- 0x0000ffff83724000
[37227.604666] VMA # 12: 0x0000ffff83724000 -- 0x0000ffff83733000
[37227.604967] VMA # 13: 0x0000ffff83733000 -- 0x0000ffff83734000
[37227.605267] VMA # 14: 0x0000ffff83734000 -- 0x0000ffff83735000
[37227.605555] VMA # 15: 0x0000ffff83735000 -- 0x0000ffff83751000
[37227.605868] VMA # 16: 0x0000ffff8375a000 -- 0x0000ffff8375e000
[37227.606198] VMA # 17: 0x0000ffff8375e000 -- 0x0000ffff8375f000
[37227.606550] VMA # 18: 0x0000ffff8375f000 -- 0x0000ffff83760000
[37227.606859] VMA # 19: 0x0000ffff83760000 -- 0x0000ffff83761000
[37227.607190] VMA # 20: 0x0000ffff83761000 -- 0x0000ffff83763000
[37227.607519] VMA # 21: 0x0000ffffca7b6000 -- 0x0000ffffca7d7000
#
# rmmod proc_info.ko
[37230.392163] proinfo_module: exit
An example of how to use kthread.
# insmod kthread_simple.ko
[ 9474.072607] kt: init
[ 9474.073518] Setup kthread...
[ 9474.076664] Start kthread...
[ 9474.077022] - Task: # 1
[ 9474.082249] kt_callback -- START
[ 9474.082694] kt_callback -- Doing working (4297260549)
# [ 9476.111992] kt_callback -- Doing working (4297261056)
r[ 9478.128113] kt_callback -- Doing working (4297261560)
mmod [ 9480.146799] kt_callback -- Doing working (4297262065)
# rmmod kthread_[ 9482.157011] kt_callback -- Doing working (4297262568)
# rmmod kthread_simple.ko
[ 9483.283668] kt: exit
[ 9484.175665] kt_callback -- END
#
An example of kthread which can put in different states using device interface.
# insmod kthread_advanced.ko.ko
[ 6135.380992] cd: init
[ 6135.390749] Setup kthread...
[ 6135.394460] Start kthread...
[ 6135.395504] - Task: # 1
[ 6135.396174] cd: device(/dev/chdev) is create
[ 6135.396968] - Major number # 235
[ 6135.397738] - minor number # 0
[ 6135.403838] kt_callback -- START
# [ 6138.411780] task_state -- running
[ 6141.579159] task_state -- running
[ 6144.610556] task_state -- running
[ 6147.719321] task_state -- running
[ 6150.742247] task_state -- running
[ 6153.808043] task_state -- running
[ 6156.849512] task_state -- running
[ 6159.874557] task_state -- running
[ 6162.898715] task_state -- running
[ 6164.638231] task_state -- suspend
[ 6188.854869] task_state -- resume
[ 6188.856184] task_state -- suspend
[ 6202.501738] task_state -- resume
[ 6205.512596] task_state -- running
[ 6208.534654] task_state -- running
[ 6211.562560] task_state -- running
[ 6214.760988] task_state -- running
[ 6217.886862] task_state -- running
[ 6220.920993] task_state -- running
[ 6223.951613] task_state -- running
[ 6226.992809] task_state -- running
[ 6230.017034] task_state -- running
[ 6233.042452] task_state -- running
[ 6235.684908] task_state -- stop
[ 6235.690136] kt_callback -- END
# rmmod kthread_advanced.ko
[ 6244.914722] cd: exit
#
# echo "1" > /dev/chdev
# echo "4" > /dev/chdev
# echo "4" > /dev/chdev
# echo "2" > /dev/chdev
An example of how to use mutex.
# insmod lock_mutex.ko
[ 7179.267261] lockmod: init
[ 7179.268022] Setup mutex...
[ 7179.268274] Setup kthread...
[ 7179.288063] Start kthreads...
[ 7179.288489] - Read task # 1
[ 7179.288761] - Write task # 1
[ 7179.289633] lockmod_read_callback -- START
[ 7179.293438] lockmod_read_callback -- Doing working (0)
[ 7179.298124] lockmod_write_callback -- START
# [ 7181.555485] lockmod_read_callback -- Doing working (0)
rmmod [ 7185.613442] lockmod_read_callback -- Doing working (2)
[ 7187.629618] lockmod_read_callback -- Doing working (2)
# rmmod lock_mutex.ko
[ 7189.584263] lockmod: exit
[ 7190.671527] lockmod_write_callback -- END
[ 7190.676295] lockmod_read_callback -- Doing working (3)
[ 7192.715941] lockmod_read_callback -- END
#
An example of how to use spin lock.
# insmod lock_spin_lock.ko
[ 7463.213732] lockmod: init
[ 7463.214213] Setup spin lock...
[ 7463.214393] Setup kthread...
[ 7463.218114] Start kthreads...
[ 7463.219204] - Read task # 1
[ 7463.219570] - Write task # 1
[ 7463.226368] lockmod_read_callback -- START
[ 7463.226826] lockmod_read_callback -- Doing working (0)
[ 7463.233915] lockmod_write_callback -- START
# [ 7465.263678] lockmod_read_callback -- Doing working (2)
[ 7467.276488] lockmod_read_callback -- Doing working (4)
[ 7469.304131] lockmod_read_callback -- Doing working (6)
[ 7471.344288] lockmod_read_callback -- Doing working (8)
[ 7473.360127] lockmod_read_callback -- Doing working (10)
[ 7475.375307] lockmod_read_callback -- Doing working (12)
[ 7477.388274] lockmod_read_callback -- Doing working (14)
rmmod [ 7479.408382] lockmod_read_callback -- Doing working (16)
# rmmod lock_s[ 7481.418612] lockmod_read_callback -- Doing working (18)
# rmmod lock_spin_lock.ko
[ 7482.256574] lockmod: exit
[ 7482.699630] lockmod_write_callback -- END
[ 7483.438937] lockmod_read_callback -- END
#
An example of how to use semaphore.
# insmod lock_semaphore.ko
[ 8589.386225] lockmod: init
[ 8589.386982] Setup mutex...
[ 8589.387193] Setup kthread...
[ 8589.394059] Start kthreads...
[ 8589.394808] - Read task # 1
[ 8589.395052] - Write task # 1
[ 8589.395939] lockmod_read_callback -- START
[ 8589.396214] lockmod_read_callback -- Doing working (0)
[ 8589.407185] lockmod_write_callback -- START
# [ 8592.431087] lockmod_read_callback -- Doing working (1)
[ 8595.522174] lockmod_read_callback -- Doing working (2)
[ 8598.571031] lockmod_read_callback -- Doing working (3)
[ 8601.611084] lockmod_read_callback -- Doing working (4)
[ 8604.650775] lockmod_read_callback -- Doing working (5)
[ 8607.692312] lockmod_read_callback -- Doing working (6)
rmmod [ 8610.733015] lockmod_read_callback -- Doing working (7)
# rmmod lock_semaphore.ko [ 8613.773242] lockmod_read_callback -- Doing working (8)
[ 8613.975061] lockmod: exit
[ 8616.812814] lockmod_write_callback -- END
[ 8616.818651] lockmod_read_callback -- Doing working (9)
[ 8618.903293] lockmod_read_callback -- END
#
An example of how to use rw-semaphore.
# insmod lock_rw_semaphore.ko
[ 9332.805410] lockmod: init
[ 9332.806475] Setup rw-semaphore...
[ 9332.806796] Setup kthread...
[ 9332.811062] Start kthreads...
[ 9332.811766] - Read task # 0: 1
[ 9332.812147] - Read task # 1: 1
[ 9332.812593] - Write task: # 1
[ 9332.816513] lockmod_read_callback0 -- START
[ 9332.816929] lockmod_read_callback0 -- Doing working (0)
[ 9332.817811] lockmod_read_callback1 -- START
[ 9332.818152] lockmod_read_callback1 -- Doing working (0)
[ 9332.832991] lockmod_write_callback -- START
# [ 9335.856640] lockmod_read_callback0 -- Doing working (1)
[ 9335.857343] lockmod_read_callback1 -- Doing working (1)
[ 9339.122699] lockmod_read_callback0 -- Doing working (2)
[ 9339.125193] lockmod_read_callback1 -- Doing working (2)
[ 9342.193709] lockmod_read_callback0 -- Doing working (3)
[ 9342.194847] lockmod_read_callback1 -- Doing working (3)
[ 9345.231656] lockmod_read_callback1 -- Doing working (4)
[ 9345.234824] lockmod_read_callback0 -- Doing working (4)
rmmod [ 9348.270767] lockmod_read_callback0 -- Doing working (5)
[ 9348.275197] lockmod_read_callback1 -- Doing working (5)
# rmmod lock_rw_semaphore.ko
[ 9351.188662] lockmod: exit
[ 9351.328923] lockmod_write_callback -- END
[ 9351.332399] lockmod_read_callback0 -- Doing working (6)
[ 9351.335479] lockmod_read_callback1 -- Doing working (6)
[ 9353.356717] lockmod_read_callback0 -- END
[ 9353.361283] lockmod_read_callback1 -- END
#
An example of how to create device interface using kernel kernel module.
# insmod char_device.ko
[10284.207744] cd: init
[10284.217666] cd: device(/dev/chdev) is create
[10284.218597] - Major number # 235
[10284.218850] - minor number # 0
# ls -l /dev/chdev
crw------- 1 root root 235, 0 Jan 29 19:04 /dev/chdev
# rmmod char_device.ko
[10298.025055] cd: exit
# ls -l /dev/c
console cpu_dma_latency
# ls -l /dev/c
A character device with FILE I/O support.
# insmod char_device_fops.ko
[10396.352119] cd: init
[10396.363753] cd: device(/dev/chdev) is create
[10396.364155] - Major number # 235
[10396.364401] - minor number # 0
# ls -l /dev/chdev
crw------- 1 root root 235, 0 Jan 29 19:05 /dev/chdev
# echo "test" > /dev/chdev
[10412.121341] cd: open
[10412.133604] cd: write (0)
[10412.135953] cd: release
[10412.136453] === Data found from user ===
[10412.137117] test
[10412.137433]
[10412.137433] ============================
#
# rmmod char_device_fops.ko
[10441.172617] cd: exit
#
A kernel module with sysfs interface.
# insmod char_device_sysfs.ko
[22321.545163] cd: init
[22321.553631] cd: device(/dev/chdev) is create
[22321.554598] - Major number # 235
[22321.554860] - Minor number # 0
[22321.555283] Sysfs interface # /sys/chdev/root
# ls -l /sys/chdev/root/
total 0
-r--r--r-- 1 root root 4096 Feb 2 03:07 readonly
-rw-r--r-- 1 root root 4096 Feb 2 03:07 readwrite
# cat /sys/chdev/root/readonly
100
# cat /sys/chdev/root/readwrite
0
# echo "10" > /sys/chdev/root/readonly
-sh: can't create /sys/chdev/root/readonly: Permission denied
# echo "10" > /sys/chdev/root/readwrite
[22364.447180] readwrite = 10
# cat /sys/chdev/root/readwrite
10
# rmmod char_device_sysfs.ko
[22377.447454] cd: exit
An example how to use timer.
# insmod timer.ko
[10872.794497] trmod: init
[10872.794922] Setup timer...
[10872.795101] Setup timeout...
# [10873.059272] trmod_timer_callback -- START
[10873.062645] trmod_timer_callback -- Doing working
[10873.064049] trmod_timer_callback -- END
# rmmod timer.ko
[10881.401745] trmod: exit
[10881.402717] Delete timer...
#
An example how to use higher resolution timer.
# insmod timer_hr.ko
[11207.958620] hr: init
[11207.959071] Setup timer...
[11207.959256] Start timer...
[11207.965159] hr_timer_callback -- START
[11207.965442] hr_timer_callback -- Doing working
[11207.965639] hr_timer_callback -- END
# rmmod timer_hr.ko
[11248.155893] hr: exit
[11248.156897] Delete timer...
#
An example how to use higher resolution timer in repetitive mode.
# insmod timer_hr_repetitive.ko
[ 7170.911353] hr: init
[ 7170.911731] Setup timer...
[ 7170.912005] Start timer...[4296684756 jiffies]
# [ 7172.917504] hr_timer_callback [4296685258 jiffies]
[ 7174.921212] hr_timer_callback [4296685759 jiffies]
[ 7176.961923] hr_timer_callback [4296686269 jiffies]
[ 7178.921332] hr_timer_callback [4296686759 jiffies]
[ 7180.914419] hr_timer_callback [4296687257 jiffies]
[ 7182.916584] hr_timer_callback [4296687758 jiffies]
[ 7184.918601] hr_timer_callback [4296688258 jiffies]
[ 7186.915450] hr_timer_callback [4296688757 jiffies]
[ 7188.921728] hr_timer_callback [4296689259 jiffies]
[ 7190.914254] hr_timer_callback [4296689757 jiffies]
[ 7192.913470] hr_timer_callback [4296690257 jiffies]
[ 7194.981200] hr_timer_callback [4296690774 jiffies]
[ 7196.914013] hr_timer_callback [4296691257 jiffies]
[ 7198.915422] hr_timer_callback [4296691757 jiffies]
[ 7200.917294] hr_timer_callback [4296692258 jiffies]
[ 7202.916724] hr_timer_callback [4296692758 jiffies]
[ 7204.917354] hr_timer_callback [4296693258 jiffies]
[ 7206.916150] hr_timer_callback [4296693757 jiffies]
[ 7208.914838] hr_timer_callback [4296694257 jiffies]
[ 7210.913370] hr_timer_callback [4296694757 jiffies]
[ 7212.917794] hr_timer_callback [4296695258 jiffies]
[ 7214.914670] hr_timer_callback [4296695757 jiffies]
[ 7216.915138] hr_timer_callback [4296696257 jiffies]
[ 7218.914531] hr_timer_callback [4296696757 jiffies]
[ 7220.915391] hr_timer_callback [4296697257 jiffies]
[ 7222.917358] hr_timer_callback [4296697758 jiffies]
[ 7224.920391] hr_timer_callback [4296698258 jiffies]
[ 7226.915757] hr_timer_callback [4296698757 jiffies]
[ 7228.915967] hr_timer_callback [4296699257 jiffies]
[ 7230.838390] hr: exit
[ 7230.838771] Delete timer...
An example of how to use tasklet.
# insmod tasklet.ko
[11354.444642] tl: init
[11354.445198] tl_tasklet_func: Tasklet data
# rmmod tasklet.ko
[11363.968424] tl: exit
#
An example of how to use wait queue.
# insmod wait_queue.ko
[ 9391.472501] wq: init
[ 9391.473955] Create work to be done...
[ 9391.475053] Create work to be done...
[ 9391.475763] wq_work_handler -- START
[ 9391.476074] wq_work_handler -- Doing working
[ 9391.476546] Going to suspend until is not done...
[ 9401.613610] wq_work_handler -- Work is done
[ 9401.616389] wq_work_handler -- END
[ 9401.617546] Wow! work is complete...
[ 9401.617838] wq: Bye!
# rmmod wait_queue.ko
[ 9405.778917] wq: exit
An example of how to use work queue.
# insmod work_queue_simple.ko
[16189.731808] wq: init
[16189.732197] Create work queue...
[16189.742714] Create work to be done...
[16189.743025] Queue a work...
[16189.743399] wq_work_handler -- START
[16189.743596] wq_work_handler -- Doing working
[16189.743901] wq: init -- end
# [16215.442424] wq_work_handler -- END
# rmmod work_queue_simple.ko
[16822.548017] wq: exit
#
An example of how to use work queue with delayed functionality.
# insmod work_queue_delayed.ko
[ 6649.250160] wq: init
[ 6649.250957] Create work queue...
[ 6649.253994] Create work to be done...
[ 6649.254922] Queue a work...
[ 6649.255207] Current time: 4296554471 jiffies
[ 6649.255641] wq: init -- end
# [ 6659.457128] wq_work_handler -- START [4296557021 jiffies]
[ 6659.461149] wq_work_handler -- Doing working
[ 6669.584246] wq_work_handler -- END
# rmmod work_queue_delayed.ko
[ 6680.596487] wq: exit
#