系统点击无法探测功能.注册错误

Question

systemtap 注册错误。

WARNING: probe process("/home/user/a.out").function("func").return inode-offset 00000000468ed0c6 registration error (rc -5)
WARNING: probe process("/home/user/a.out").function("func").call inode-offset 00000000468ed0c6 registration error (rc -5)
WARNING: task_finder mmap inode-uprobes callback for task 28532 failed: -5

我正在学习系统点击。我有一个在 while 循环中调用函数的过程。当我使用"stap -v test.stp"启动systemtap来探测用户空间函数时，我收到注册错误。以下是完整的屏幕截图;

Pass 1: parsed user script and 465 library scripts using 112640virt/48788res/6452shr/42636data kb, in 100usr/20sys/123real ms.
Pass 2: analyzed script: 3 probes, 2 functions, 4 embeds, 3 globals using 114256virt/51968res/7840shr/44252data kb, in 50usr/110sys/162real ms.
Pass 3: using cached /root/.systemtap/cache/66/stap_662fe7689c5fb5d6ef569e8246fa1c8a_3296.c
Pass 4: using cached /root/.systemtap/cache/66/stap_662fe7689c5fb5d6ef569e8246fa1c8a_3296.ko
Pass 5: starting run.
WARNING: probe process("/home/admin/a.out").function("func").return inode-offset 00000000468ed0c6 registration error (rc 0)
WARNING: probe process("/home/admin/a.out").function("func").call inode-offset 00000000468ed0c6 registration error (rc 0)
^CERROR: empty aggregate near operator '@max' at test.stp:6:37
WARNING: Number of errors: 1, skipped probes: 0
WARNING: /usr/bin/staprun exited with status: 1
Pass 5: run completed in 0usr/20sys/9318real ms.
Pass 5: run failed.  [man error::pass5]

test.stp

probe process("/home/user/a.out").function("func").return {
stats <<< gettimeofday_ns() - @entry(gettimeofday_ns())
}
probe end {
printf("max/avg/min: %d/%d/%dn", @max(stats), @avg(stats), @min(stats))
print(@hist_log(stats))
}
global stats

测试.c

#include <stdlib.h>
#include <unistd.h>
void func()
{
printf("Hellon");
sleep(1);
}
int main()
{
while (1)
{
func();
}
}

Answer 1

systemtap 不支持覆盖/联合文件系统。必须更改 systemtap 用户空间代码才能获取文件的真实索引节点(如果该文件位于 overlayfs 中(。为此，需要对系统tap进行代码更改和构建。下载系统点击源代码 在文件uprobes-inode.c中进行更改。更改是使用d_backing_inode查找inode。需要在两个地方进行更改。

inode_1 = d_backing_inode(d_real((struct dentry *) dentry, NULL, 0, 0)); //use inode_1 in the following function.
if ((vm_flags & VM_EXEC) && !(vm_flags & VM_WRITE))
rc = stapiu_change_plus(target, task, addr, length,
offset, vm_flags, inode_1);
//          offset, vm_flags, dentry->d_inode);

vm_file = stap_find_exe_file(mm);
if (vm_file) {
if (vm_file->f_path.dentry)
{
//inode = vm_file->f_path.dentry->d_inode;
inode = d_backing_inode(d_real((struct dentry *) vm_file->f_path.dentry, NULL, 0, 0));

}
fput(vm_file);