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我正在使用 DKMS 在 Debian 发行版上构建 Linux 模块，并且我需要调试内核冻结。

我已经安装了crash带有内核调试符号的命令行工具。当发生冻结时，我有一个使用crash命令加载的崩溃文件，我可以从内核跟踪中看到每一行的文件名和行号，但是当它是关于我的模块时，我没有任何文件名，也不是行号。

这是一个例子：

WARNING: active task ffff98d215239e80 on cpu 1 not found in PID hash

      KERNEL: /usr/lib/debug/boot/vmlinux-4.19.0-8-amd64
    DUMPFILE: /var/crash/202004292108/dump.202004292108  [PARTIAL DUMP]
        CPUS: 12
        DATE: Wed Apr 29 21:07:00 2020
      UPTIME: 00:13:32
LOAD AVERAGE: 0.62, 0.57, 0.37
       TASKS: 886
    NODENAME: debian
     RELEASE: 4.19.0-8-amd64
     VERSION: #1 SMP Debian 4.19.98-1+deb10u1 (2020-04-27)
     MACHINE: x86_64  (3700 Mhz)
      MEMORY: 16 GB
       PANIC: "BUG: unable to handle kernel NULL pointer dereference at 0000000000000018"
         PID: 15775
     COMMAND: "douaned"
        TASK: ffff98d215239e80  [THREAD_INFO: ffff98d215239e80]
         CPU: 1
       STATE: EXIT_DEAD (PANIC)

crash> bt -l
PID: 15775  TASK: ffff98d215239e80  CPU: 1   COMMAND: "douaned"
 #0 [ffff98d36e843870] machine_kexec at ffffffff87656967
    ./debian/build/build_amd64_none_amd64/./arch/x86/include/asm/mem_encrypt.h: 75
 #1 [ffff98d36e8438c8] __crash_kexec at ffffffff877213ad
    ./debian/build/build_amd64_none_amd64/./kernel/kexec_core.c: 958
 #2 [ffff98d36e843990] crash_kexec at ffffffff877221fd
    ./debian/build/build_amd64_none_amd64/./include/linux/compiler.h: 219
 #3 [ffff98d36e8439a8] oops_end at ffffffff8762a0ad
    ./debian/build/build_amd64_none_amd64/./arch/x86/kernel/dumpstack.c: 334
 #4 [ffff98d36e8439c8] no_context at ffffffff876653ee
    ./debian/build/build_amd64_none_amd64/./arch/x86/mm/fault.c: 808
 #5 [ffff98d36e843a20] __do_page_fault at ffffffff87665ab2
    ./debian/build/build_amd64_none_amd64/./arch/x86/mm/fault.c: 1323
 #6 [ffff98d36e843a90] page_fault at ffffffff87e0114e
    /build/linux-AqT5hv/linux-4.19.98/arch/x86/entry/entry_64.S: 1204
    [exception RIP: idr_find]
    RIP: ffffffff87d0b860  RSP: ffff98d36e843b40  RFLAGS: 00010246
    RAX: 0000000000000000  RBX: ffff98d20e848000  RCX: 0000000000000000
    RDX: 000000009456dad9  RSI: 0000000000005807  RDI: 0000000000000008
    RBP: ffff98d363bc3ae8   R8: 000000000001421d   R9: 00000000917bc5e0
    R10: ffff98d36e843bae  R11: 0000000000000049  R12: 0000000000000004
    R13: ffff98d226491480  R14: ffff98d206f28cfc  R15: ffff98d206f28d10
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
    ./debian/build/build_amd64_none_amd64/./lib/idr.c: 177
 #7 [ffff98d36e843b40] find_get_pid at ffffffff8769e846
    ./debian/build/build_amd64_none_amd64/./include/linux/pid.h: 71
 #8 [ffff98d36e843b48] netfiler_packet_hook at ffffffffc1962eda [douane]
 #9 [ffff98d36e843ce8] nf_hook_slow at ffffffff87c2eea4
    ./debian/build/build_amd64_none_amd64/./net/netfilter/core.c: 512
#10 [ffff98d36e843d18] __ip_local_out at ffffffff87c3c8a7
    ./debian/build/build_amd64_none_amd64/./include/linux/netfilter.h: 248
#11 [ffff98d36e843d70] ip_local_out at ffffffff87c3c927
    ./debian/build/build_amd64_none_amd64/./net/ipv4/ip_output.c: 123
...

看看第 8 行。

从 DKMS 文档中，我找到了STRIPE=[#]我传递的配置，no以便不删除调试符号（如文档所述），但我仍然没有任何文件名或行号。

谁能告诉我如何让它们显示？

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1 回答 1

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我终于想通了 ！

您首先需要知道您的内核模块文件安装在哪里（douane.ko在我的情况下，它安装在/lib/modules/$(uname -r)/updates/dkms/），然后在加载崩溃文件后，就像问题中显示的那样，您需要使用加载模块的调试符号mod命令：

crash> mod -s douane /lib/modules/4.19.0-8-amd64/updates/dkms/douane.ko
     MODULE       NAME                       SIZE  OBJECT FILE
ffffffffc17f8040  douane                     28672 /lib/modules/4.19.0-8-amd64/updates/dkms/douane.ko

从现在开始，使用bt -l也会显示内核模块源代码中的行号。

于 2020-05-25T19:05:02.730 回答