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Re: problem in User-Space Probing
- From: Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>
- To: ch huang <justlooks at gmail dot com>
- Cc: systemtap at sourceware dot org
- Date: Tue, 6 Mar 2012 10:17:28 +0530
- Subject: Re: problem in User-Space Probing
- References: <CACeqxwT-v_fXLYdm6+FcCH5E+TSWQifbkY_n=Jnb7hk+xpa5+w@mail.gmail.com>
- Reply-to: Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>
>
> probe process("/root/test").function("my_out"){
> printf("i in %s\n",pp())
> }
> probe process("/root/test").function("my_out").return{
> printf("back from %s\n",probefunc())
> }
> when i run this script i find some warning information
>
> # stap exec.stp
> /usr/local/share/systemtap/runtime/uprobes/uprobes.c: In function
> ?uprobe_report_exec?:
> /usr/local/share/systemtap/runtime/uprobes/uprobes.c:2401: warning:
> ?uproc? may be used uninitialized in this function
> /usr/local/share/systemtap/runtime/uprobes/uprobes.c: In function
> ?uprobe_report_exit?:
> /usr/local/share/systemtap/runtime/uprobes/uprobes.c:2101: warning:
> ?uproc? may be used uninitialized in this function
> i in process("/root/test").function("my_out@/root/test.c:4")
> back from my_out
>
> it seems script works fine ,but i do not know the warning info,is
> there something i missed?
>
It would have been good if you had given your stap setup details.
I think you are running on a kernel < 2.6.24.
>From the code walk through, I dont see a case for uproc being not
initialized. I think its a compiler bug.
https://lkml.org/lkml/2011/11/28/287
--
Thanks and Regards
Srikar