Jim Huang
f8adcdb3c1
procfs4: Shorten and indent
2021-08-07 10:54:19 +08:00
Jim Huang
466e8a00fd
cat_nonblock: Use canonical name scheme and fix unintended assignment
2021-08-05 14:28:12 +08:00
RinHizakura
5940dd9faa
Revise hello-5 and its output ( #38 )
...
For the example module hello_5, the book showed the incorrect output
in corresponding with its execution results.
In addition, this patch changes from myintArray[2] = {-1, -1} to
myintArray[2] = {420, 420}, which help the readers distinguish from
the kernel messages.
2021-08-04 23:42:10 +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
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
25077667
00f7e7018f
Fix trivial tweak for missing comma
2021-07-26 03:08:27 +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
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
2246e20809
Add LaTeX script and sample code
2021-07-22 06:35:24 +08:00
