xref: /linux/Documentation/translations/zh_CN/dev-tools/ubsan.rst (revision 8815da98e06a930ce7e6a1ffaf1b1590e79fd94f) 
1.. SPDX-License-Identifier: GPL-2.0
2
3.. include:: ../disclaimer-zh_CN.rst
4
5:Original: Documentation/dev-tools/ubsan.rst
6:Translator: Dongliang Mu <dzm91@hust.edu.cn>
7
8未定义行为消毒剂 - UBSAN
9====================================
10
11UBSAN是一种动态未定义行为检查工具。
12
13UBSAN使用编译时插桩捕捉未定义行为。编译器在可能导致未定义行为的操作前插入特定
14检测代码。如果检查失败，即检测到未定义行为，__ubsan_handle_* 函数将被调用打印
15错误信息。
16
17GCC自4.9.x [1_] （详见 ``-fsanitize=undefined`` 选项及其子选项）版本后引入这
18一特性。GCC 5.x 版本实现了更多检查器 [2_]。
19
20报告样例
21--------------
22
23::
24
25	 ================================================================================
26	 UBSAN: Undefined behaviour in ../include/linux/bitops.h:110:33
27	 shift exponent 32 is to large for 32-bit type 'unsigned int'
28	 CPU: 0 PID: 0 Comm: swapper Not tainted 4.4.0-rc1+ #26
29	  0000000000000000 ffffffff82403cc8 ffffffff815e6cd6 0000000000000001
30	  ffffffff82403cf8 ffffffff82403ce0 ffffffff8163a5ed 0000000000000020
31	  ffffffff82403d78 ffffffff8163ac2b ffffffff815f0001 0000000000000002
32	 Call Trace:
33	  [<ffffffff815e6cd6>] dump_stack+0x45/0x5f
34	  [<ffffffff8163a5ed>] ubsan_epilogue+0xd/0x40
35	  [<ffffffff8163ac2b>] __ubsan_handle_shift_out_of_bounds+0xeb/0x130
36	  [<ffffffff815f0001>] ? radix_tree_gang_lookup_slot+0x51/0x150
37	  [<ffffffff8173c586>] _mix_pool_bytes+0x1e6/0x480
38	  [<ffffffff83105653>] ? dmi_walk_early+0x48/0x5c
39	  [<ffffffff8173c881>] add_device_randomness+0x61/0x130
40	  [<ffffffff83105b35>] ? dmi_save_one_device+0xaa/0xaa
41	  [<ffffffff83105653>] dmi_walk_early+0x48/0x5c
42	  [<ffffffff831066ae>] dmi_scan_machine+0x278/0x4b4
43	  [<ffffffff8111d58a>] ? vprintk_default+0x1a/0x20
44	  [<ffffffff830ad120>] ? early_idt_handler_array+0x120/0x120
45	  [<ffffffff830b2240>] setup_arch+0x405/0xc2c
46	  [<ffffffff830ad120>] ? early_idt_handler_array+0x120/0x120
47	  [<ffffffff830ae053>] start_kernel+0x83/0x49a
48	  [<ffffffff830ad120>] ? early_idt_handler_array+0x120/0x120
49	  [<ffffffff830ad386>] x86_64_start_reservations+0x2a/0x2c
50	  [<ffffffff830ad4f3>] x86_64_start_kernel+0x16b/0x17a
51	 ================================================================================
52
53用法
54-----
55
56使用如下内核配置启用UBSAN::
57
58	CONFIG_UBSAN=y
59
60使用如下内核配置检查整个内核::
61
62        CONFIG_UBSAN_SANITIZE_ALL=y
63
64为了在特定文件或目录启动代码插桩，需要在相应的内核Makefile中添加一行类似内容:
65
66- 单文件（如main.o）::
67
68    UBSAN_SANITIZE_main.o := y
69
70- 一个目录中的所有文件::
71
72    UBSAN_SANITIZE := y
73
74即使设置了``CONFIG_UBSAN_SANITIZE_ALL=y``，为了避免文件被插桩，可使用::
75
76  UBSAN_SANITIZE_main.o := n
77
78与::
79
80  UBSAN_SANITIZE := n
81
82未对齐的内存访问检测可通过开启独立选项 - CONFIG_UBSAN_ALIGNMENT 检测。
83该选项在支持未对齐访问的架构上(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y)
84默认为关闭。该选项仍可通过内核配置启用，但它将产生大量的UBSAN报告。
85
86参考文献
87----------
88
89.. _1: https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
90.. _2: https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
91.. _3: https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html
92