使用systemtap和kprobe跟踪自己开发的模块

case_使用systemtap和kprobe跟踪自己开发的模块.txt

因为之前看到有篇文档说systemtap跟踪不了内核模块，所以看个究竟，发现是错误的说法

1.sles11sp1:/opt/proc_mtest # ls
Makefile  mtest.stp  proc_mtest.c  proc_mtest.ko.debug  trace_mtest.c

 2.kprobe 正常跟踪， 结论：kprobe可以跟踪模块中的函数。
Jan  1 07:41:34 sles11sp1 kernel: [ 3898.313236] Registered a jprobe.
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475312] mtest_openprocess cat pid=4432
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475352] Pid: 4432, comm: cat Tainted: P          N  2.6.32.59-0.7-default #1
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475355] Call Trace:
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475370]  [] dump_trace+0x6c/0x2d0
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475377]  [] dump_stack+0x69/0x73
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475385]  [] jmtest_read+0x2d/0x38 [trace_mtest]
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475413]  [] proc_reg_read+0x77/0xc0
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475428]  [] vfs_read+0xc7/0x130
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475434]  [] sys_read+0x53/0xa0
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475440]  [] system_call_fastpath+0x16/0x1b
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475454]  [<00007f9c06205f30>] 0x7f9c06205f30
Jan  1 07:42:31 sles11sp1 kernel: [ 3955.475471] mtest_read

2.systemtap跟踪
 sles11sp1:/opt/proc_mtest # cat mtest.stp

probe module("proc_mtest").function("mtest_read")
{
    printf( "mtest read by traced")
}


sles11sp1:/opt/proc_mtest # stap mtest.stp
semantic error: missing x86_64 kernel/module debuginfo under '/lib/modules/2.6.32.59-0.7-default/build' while resolving probe point module("proc_mtest").function("mtest_read")
Pass 2: analysis failed.  Try again with another '--vp 01' option.
失败。


定位：strace 一下
sles11sp1:/opt/proc_mtest # strace -o a  stap mtest.stp
semantic error: missing x86_64 kernel/module debuginfo under '/lib/modules/2.6.32.59-0.7-default/build' while resolving probe point module("proc_mtest").function("mtest_read")
Pass 2: analysis failed.  Try again with another '--vp 01' option.

发现去找/lib/modules/2.6.32.59-0.7-default/kernel 下面的各个ko,于是乎


sles11sp1:/opt/proc_mtest # cp proc_mtest.ko  /lib/modules/2.6.32.59-0.7-default/kernel/drivers/
sles11sp1:/opt/proc_mtest # strace -o b  stap mtest.stp
^Csles11sp1:/opt/proc_mtest # stap mtest.stp
mtest read by traced


OK，解决。