| .. SPDX-License-Identifier: GPL-2.0 |
| |
| .. include:: ../disclaimer-zh_CN.rst |
| |
| :Original: Documentation/dev-tools/ubsan.rst |
| :Translator: Dongliang Mu <dzm91@hust.edu.cn> |
| |
| 未定义行为消毒剂 - UBSAN |
| ==================================== |
| |
| UBSAN是一种动态未定义行为检查工具。 |
| |
| UBSAN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 |
| 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 |
| 错误信息。 |
| |
| GCC自4.9.x [1_] (详见 ``-fsanitize=undefined`` 选项及其子选项)版本后引入这 |
| 一特性。GCC 5.x 版本实现了更多检查器 [2_]。 |
| |
| 报告样例 |
| -------------- |
| |
| :: |
| |
| ================================================================================ |
| UBSAN: Undefined behaviour in ../include/linux/bitops.h:110:33 |
| shift exponent 32 is to large for 32-bit type 'unsigned int' |
| CPU: 0 PID: 0 Comm: swapper Not tainted 4.4.0-rc1+ #26 |
| 0000000000000000 ffffffff82403cc8 ffffffff815e6cd6 0000000000000001 |
| ffffffff82403cf8 ffffffff82403ce0 ffffffff8163a5ed 0000000000000020 |
| ffffffff82403d78 ffffffff8163ac2b ffffffff815f0001 0000000000000002 |
| Call Trace: |
| [<ffffffff815e6cd6>] dump_stack+0x45/0x5f |
| [<ffffffff8163a5ed>] ubsan_epilogue+0xd/0x40 |
| [<ffffffff8163ac2b>] __ubsan_handle_shift_out_of_bounds+0xeb/0x130 |
| [<ffffffff815f0001>] ? radix_tree_gang_lookup_slot+0x51/0x150 |
| [<ffffffff8173c586>] _mix_pool_bytes+0x1e6/0x480 |
| [<ffffffff83105653>] ? dmi_walk_early+0x48/0x5c |
| [<ffffffff8173c881>] add_device_randomness+0x61/0x130 |
| [<ffffffff83105b35>] ? dmi_save_one_device+0xaa/0xaa |
| [<ffffffff83105653>] dmi_walk_early+0x48/0x5c |
| [<ffffffff831066ae>] dmi_scan_machine+0x278/0x4b4 |
| [<ffffffff8111d58a>] ? vprintk_default+0x1a/0x20 |
| [<ffffffff830ad120>] ? early_idt_handler_array+0x120/0x120 |
| [<ffffffff830b2240>] setup_arch+0x405/0xc2c |
| [<ffffffff830ad120>] ? early_idt_handler_array+0x120/0x120 |
| [<ffffffff830ae053>] start_kernel+0x83/0x49a |
| [<ffffffff830ad120>] ? early_idt_handler_array+0x120/0x120 |
| [<ffffffff830ad386>] x86_64_start_reservations+0x2a/0x2c |
| [<ffffffff830ad4f3>] x86_64_start_kernel+0x16b/0x17a |
| ================================================================================ |
| |
| 用法 |
| ----- |
| |
| 使用如下内核配置启用UBSAN:: |
| |
| CONFIG_UBSAN=y |
| |
| 使用如下内核配置检查整个内核:: |
| |
| CONFIG_UBSAN_SANITIZE_ALL=y |
| |
| 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: |
| |
| - 单文件(如main.o):: |
| |
| UBSAN_SANITIZE_main.o := y |
| |
| - 一个目录中的所有文件:: |
| |
| UBSAN_SANITIZE := y |
| |
| 即使设置了``CONFIG_UBSAN_SANITIZE_ALL=y``,为了避免文件被插桩,可使用:: |
| |
| UBSAN_SANITIZE_main.o := n |
| |
| 与:: |
| |
| UBSAN_SANITIZE := n |
| |
| 未对齐的内存访问检测可通过开启独立选项 - CONFIG_UBSAN_ALIGNMENT 检测。 |
| 该选项在支持未对齐访问的架构上(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y) |
| 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。 |
| |
| 参考文献 |
| ---------- |
| |
| .. _1: https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html |
| .. _2: https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html |
| .. _3: https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html |