[lttng-dev] lttng kretprobe issue

[tarek slaymia]

Hi all

i replace a syscall function address of sys_write by my_own_write function
using an LKM module as follow:

xchg(&sys_call_table[__NR_write],my_own_write);

In the normal case the content of sys_call_table[__NR_write] address
changes and it displays the address of my_own_write , i verify this using a
simple printk and i see that the address changes.

I have an issue when tracing this change using lttng kretprobe , i use the
following event :

lttng enable-event sys_write -k --function sys_write

 The ip value of sys_write in the lttng traces ( the same address of
sys_call_table[__NR_write] ) remains the same even after changing it by the
new function address (address of my_own_write)
Why the ip value of sys_write syscall displayed in lttng traces remains the
same even after changing it ?

Best regards.
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