linD026
6b6b6635cf
CI: Introduce Smatch for static analysis ( #125 )
...
Smatch[1][2] is a pluggable static analysis for C. It may help us find
out the potential problem of the example code.
Doing with smatch, if set the --file-output flag, it will generate the
{}.c.smatch report for each c file. This will make a little bit
complicated to collect all the report messages. So, here we stay at the
default setting, stdout for the smatch messages.
For more information, see:
- https://lwn.net/Articles/696624/
- https://elinux.org/images/d/d3/Bargmann.pdf
Also, fix the warning from Smatch:
Smatch failed: 1 warning(s), 1 error(s)
lkmpg/examples/procfs2.c:57 procfile_write() error: buffer overflow 'procfs_buffer' 1024 <= 1024
lkmpg/examples/kbleds.c:58 kbleds_init() warn: argument 5 to %lx specifier is cast from pointer
Furthermore, the effect of the write operation in procfs2.c is too
implied. So after writing, print the buffer every time.
Close #122
[1] https://github.com/error27/smatch
[2] https://repo.or.cz/w/smatch.git
2021-11-01 08:20:41 +08:00
linD026
9289bfe59c
Fix the warnings raised by Sparse ( #92 )
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Sparse[1] is a semantic parser, capable of finding out the potential
problems of Linux kernel code. This patch fixed the warnings.
[1] https://www.kernel.org/doc/html/latest/dev-tools/sparse.html
2021-09-04 17:53:29 +08:00
linD026
eef2bc4395
Enforce Linux kernel coding style ( #88 )
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The only exception is to indent with four spaces rather than tabs
for sticking to compact layout of source listing.
Close #87
2021-09-02 15:15:07 +08:00
Jim Huang
10c7a9433a
Apply editorial changes
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This patch makes source listing shorter and more compact, that helps
when browsing.
2021-08-08 01:24:59 +08:00
Jim Huang
d43259c553
Drop the deprecated init_module() and cleanup_module()
2021-08-08 00:29:24 +08:00
Jim Huang
a26d93037e
Enforce consistent style
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Execute "make indent" before submitting patches.
2021-08-07 23:33:37 +08:00
linD026
c7a7a667cf
Avoid strlen by assigning explicit length of string for proc_read ( #18 )
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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
faf3aa7c22
Make each source file more consistent
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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
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
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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
