Re: [patch] For getrusage's argstr in tapset

[Wenji Huang <wenji dot huang at oracle dot com>]

Hi zhaolei,

  In normal case, thing may be like that. But in abnormal case, maybe 
wrong arguments are passed to this function. So new entry will
give a clearer description, instead of general UNKNOWN.

Thanks,
Wenji
  
Zhaolei wrote:

> Hello, Wenji.
>
> Thank you for your suggestion.
>
> I investigated RUSAGE_BOTH and got the following result:
> 1: _rusage_who_str is only used for sys_getrusage(and compat_sys_getrusage)
> in current tapset, and there is no other syscall which needs to call
> _rusage_who_str.
>
> 2: RUSAGE_BOTH is only used in kernel's internal function getrusage, but
> there is no syscall using this function with RUSAGE_BOTH.
>
> So I think RUSAGE_BOTH is not necessary in tracing syscall, but it may be
> needed when tracing kernel function as getrusage.
>
> It is good idea disable RUSAGE_BOTH only in sys_getrusage
> (and compat_sys_getrusage).
>
> Regards
> Zhaolei
> ----- Original Message ----- 
> From: "Wenji Huang" <wenji.huang@oracle.com>
> To: "Zhaolei" <zhaolei@cn.fujitsu.com>
> Cc: <systemtap@sourceware.org>
> Sent: Monday, September 10, 2007 11:44 AM
> Subject: Re: [patch] For getrusage's argstr in tapset
>
>
>  
>
> > Hi Zhaolei,
> >
> >    probe getrusage set probe point at the entry of the function. So the 
> > arguments may be any value.
> >  
> >    So I think to keep the entry in _rusage_who_str, just give another 
> > mapping in case of some certain value.
> >
> >    Of course, if you can ensure that "who" only be 
> > RUSAGE_SELF/RUSAGE_CHILDREN when the syscall called. Just remove.
> >
> > Thanks,
> > Wenji
> >
> >
> > Zhaolei wrote:
> >
> >    
> >
> > > Hi, everyone
> > >
> > > In [tapset->probe getrusage], argstr's "who" argument is printed as
> > > "RUSAGE_BOTH" when its value is -2.
> > > But "RUSAGE_BOTH" is not used in getrusage syscall due to the following
> > > kernel source:
> > > asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
> > > {
> > >       if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
> > >               return -EINVAL;
> > >       return getrusage(current, who, ru);
> > > }
> > >
> > > So i want to remove RUSAGE_BOTH from _rusage_who_str.
> > > Is there anyone knows why RUSAGE_BOTH is necessary, please tell me.
> > > and if no objection, I will commit it.
> > >
> > > Signed-off-by: "Zhaolei" zhaolei@cn.fujitsu.com
> > >
> > > --- aux_syscalls.stp.old        2007-09-06 11:51:14.000000000 +0900
> > > +++ aux_syscalls.stp    2007-09-06 11:52:22.000000000 +0900
> > > @@ -1661,7 +1661,6 @@ function _rlimit_resource_str(r) {
> > > function _rusage_who_str(w) {
> > >   if(w==0) return "RUSAGE_SELF"
> > >   if(w==-1) return "RUSAGE_CHILDREN"
> > > -   if(w==-2) return "RUSAGE_BOTH"
> > >   return sprintf("UNKNOWN VALUE: %d", w)
> > > }
> > >
> > > Regards
> > > Zhaolei
> > >
> > >
> > >
> > >      
> >    
>
>