Commit Graph

88 Commits

Author SHA1 Message Date
fennecj
5d2f428cff Fix grammar 2021-07-31 23:19:44 +08:00
demonsome
50e9d9176f
chardev: Revise comment on device node (#23)
The device file create in this example is "chardev". 
So input command "sudo cat /dev/chardev" will get a valid message
"I already told you %d times Hello world!"
2021-07-31 23:03:16 +08:00
fennecJ
a4af7b5e5a
Fix dead link (#21) 2021-07-30 14:47:22 +08:00
Jim Huang
377ec93a05 Add information for contributing 2021-07-30 13:45:58 +08:00
Jim Huang
b50323330c
Merge pull request #19 from fennecJ/master
Fix typo
2021-07-30 00:40:58 +08:00
fennecj
69b40b7bda Fix typo 2021-07-29 19:52:22 +08:00
linD026
c7a7a667cf
Avoid strlen by assigning explicit length of string for proc_read (#18)
Since the address of buffer is userspace address, it may trigger an unexpected fault on strlen(buffer).

On Ubuntu 20.04.2 LTS ( 5.8.0-63-generic ), using strlen(buffer) will result in the following:
[ 2168.010930] /proc/buffer1k created
[ 2177.014347] BUG: unable to handle page fault for address: 00007fbbc2a17000
[ 2177.014355] #PF: supervisor read access in kernel mode
[ 2177.014358] #PF: error_code(0x0000) - not-present page
[ 2177.014361] PGD 80000003c61d0067 P4D 80000003c61d0067 PUD 3ee6c5067 PMD 40e1ff067 PTE 0
[ 2177.014369] Oops: 0000 [#1] SMP PTI
[ 2177.014376] CPU: 7 PID: 4750 Comm: cat Tainted: P        W  OE     5.8.0-63-generic #71~20.04.1-Ubuntu

[ 2177.014387] RIP: 0010:procfile_read+0xb/0x20 [procfs2]
[ 2177.014393] Code: Unable to access opcode bytes at RIP 0xffffffffc1253fe1.
[ 2177.014396] RSP: 0018:ffffbc84412cbe78 EFLAGS: 00010286
[ 2177.014400] RAX: ffffffffc1254000 RBX: 0000000000020000 RCX: ffffbc84412cbef0
[ 2177.014403] RDX: 0000000000020000 RSI: 00007fbbc2a17000 RDI: ffffa057d2708f00
[ 2177.014406] RBP: ffffbc84412cbe80 R08: 0000000000000001 R09: 0000000000000000
[ 2177.014409] R10: 0000000000000000 R11: 0000000000000000 R12: ffffa0581de8ccc0
[ 2177.014411] R13: ffffa057d2708f00 R14: ffffbc84412cbef0 R15: 00007fbbc2a17000
[ 2177.014415] FS:  00007fbbc3bfa580(0000) GS:ffffa0582dbc0000(0000) knlGS:0000000000000000
[ 2177.014418] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2177.014421] CR2: ffffffffc1253fe1 CR3: 00000003c611c004 CR4: 00000000003606e0
[ 2177.014424] Call Trace:
[ 2177.014435]  proc_reg_read+0x66/0x90
[ 2177.014441]  vfs_read+0xaa/0x190
[ 2177.014446]  ksys_read+0x67/0xe0
[ 2177.014451]  __x64_sys_read+0x1a/0x20
[ 2177.014458]  do_syscall_64+0x49/0xc0
[ 2177.014464]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 2177.014467] RIP: 0033:0x7fbbc3b18142
[ 2177.014472] Code: c0 e9 c2 fe ff ff 50 48 8d 3d 3a ca 0a 00 e8 f5 19 02 00 0f 1f 44 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 0f 05 <48> 3d 00 f0 ff ff 77 56 c3 0f 1f 44 00 00 48 83 ec 28 48 89 54 24
[ 2177.014476] RSP: 002b:00007ffcf2d20d78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 2177.014479] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007fbbc3b18142
[ 2177.014482] RDX: 0000000000020000 RSI: 00007fbbc2a17000 RDI: 0000000000000003
[ 2177.014485] RBP: 00007fbbc2a17000 R08: 00007fbbc2a16010 R09: 0000000000000000
[ 2177.014487] R10: 0000000000000022 R11: 0000000000000246 R12: 0000560f8ff081f0
[ 2177.014490] R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000

[ 2177.014635] CR2: 00007fbbc2a17000
[ 2177.014639] ---[ end trace b71ff05c1b0a10f6 ]---
[ 2177.184174] RIP: 0010:procfile_read+0xb/0x20 [procfs2]
[ 2177.184176] Code: Unable to access opcode bytes at RIP 0xffffffffc1253fe1.
[ 2177.184177] RSP: 0018:ffffbc84412cbe78 EFLAGS: 00010286
[ 2177.184178] RAX: ffffffffc1254000 RBX: 0000000000020000 RCX: ffffbc84412cbef0
[ 2177.184179] RDX: 0000000000020000 RSI: 00007fbbc2a17000 RDI: ffffa057d2708f00
[ 2177.184180] RBP: ffffbc84412cbe80 R08: 0000000000000001 R09: 0000000000000000
[ 2177.184180] R10: 0000000000000000 R11: 0000000000000000 R12: ffffa0581de8ccc0
[ 2177.184181] R13: ffffa057d2708f00 R14: ffffbc84412cbef0 R15: 00007fbbc2a17000
[ 2177.184182] FS:  00007fbbc3bfa580(0000) GS:ffffa0582dbc0000(0000) knlGS:0000000000000000
[ 2177.184182] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2177.184183] CR2: ffffffffc1253fe1 CR3: 00000003c611c004 CR4: 00000000003606e0
2021-07-29 16:10:52 +08:00
Jim Huang
a82cf74c15 Open Software License is not popular. Explicitly refer to OSI 2021-07-27 10:10:16 +08:00
2011eric
d0f604fc26
Use unified command prompt (#11)
This patch enforces the assumption of using as a non-root user. That is,
it is necessary to specify sudo for the essential commands such as
insmod and rmmod. In addition, most command prompts should start with
$ (dollar sign).
2021-07-26 13:10:34 +08:00
Jim Huang
cb5ae95673
Merge pull request #12 from 25077667/style-tweaks
Fix trivial tweak for missing comma
2021-07-26 03:18:06 +08:00
25077667
00f7e7018f Fix trivial tweak for missing comma 2021-07-26 03:08:27 +08:00
Jim Huang
65a8c123e4 Tidy section: hello world 2021-07-26 01:46:26 +08:00
Wei-Lun Tsai
ddcbb69fa3
Trivial fix for writing style 2021-07-24 09:14:46 +08:00
Jim Huang
1e3c1b8a76 Apply trivial tweak 2021-07-23 14:36:26 +08:00
Jim Huang
40ae17c1f8
Merge pull request #2 from 25077667/master
Redraw figure: seq_file
2021-07-23 14:33:30 +08:00
Jim Huang
78ca9884de
Merge pull request #3 from ekangmonyet/minor-fixes
Typo at 0.7.3 Manage /proc file with seq_file
2021-07-23 14:31:18 +08:00
Jim Huang
75356dbe43 Tidy section: hello world 2021-07-23 14:30:09 +08:00
Jim Huang
9b05bf44dd Tweak wording 2021-07-23 14:05:52 +08:00
Jim Huang
58e55d03d0 Tidy section: headers 2021-07-23 14:02:27 +08:00
Jim Huang
f7f46f145d Tidy section: introduction 2021-07-23 13:56:51 +08:00
Ekang Monyet
121d816282 Typo at 0.7.3 Manage /proc file with seq_file 2021-07-23 11:07:17 +08:00
25077667
245ac0298e Use TikZ to re-draw seq_file graph 2021-07-23 02:10:57 +08:00
Jim Huang
35ac926de5 Remove unused packages 2021-07-22 20:47:48 +08:00
Jim Huang
faf3aa7c22 Make each source file more consistent
It is vital to denote the file name and summary for each source,
otherwise readers could not figure out the corresponding files.
2021-07-22 11:25:32 +08:00
Jim Huang
1c93f2f5ef Shorten sample code 2021-07-22 10:55:14 +08:00
Jim Huang
52dfb6744d Use American English words 2021-07-22 10:54:24 +08:00
Jim Huang
2e30e181f8 Drop duplicated copyright notice 2021-07-22 10:53:45 +08:00
Jim Huang
b76e5d378e Reduce header inclusion 2021-07-22 10:31:24 +08:00
Jim Huang
08e7b6efc3 Emphasize on 5.x kernel 2021-07-22 08:31:47 +08:00
Jim Huang
60856826f0 Exclude the files generated by Linux kernel build system 2021-07-22 08:09:20 +08:00
Jim Huang
d8812d2d9a Revise the authorship 2021-07-22 07:39:35 +08:00
Jim Huang
675c002b15 Remove linux-2.6 specific checks 2021-07-22 07:33:27 +08:00
Jim Huang
760bbe70cb Drop duplicated module author information 2021-07-22 07:29:07 +08:00
Jim Huang
64f791f274 Improve the compatibility with kernel version < 5.6 2021-07-22 07:17:31 +08:00
Jim Huang
50b8dfe6c2 Enforce the customized style for example code
Instead of using tab for indention, the style defaults to 4 spaces for
the sake of compact layout.
2021-07-22 06:58:13 +08:00
Jim Huang
936d82fad7 Emphasize on the license terms 2021-07-22 06:39:22 +08:00
Jim Huang
2246e20809 Add LaTeX script and sample code 2021-07-22 06:35:24 +08:00
Jim Huang
826b45b3d9 Initial import 2021-07-22 06:34:19 +08:00