Re: [PATCH] Fix compilation errors for itrace probe point - v2

[Maynard Johnson <maynardj at us dot ibm dot com>]

Maynard Johnson wrote:
> Maynard Johnson wrote:
> > David Smith wrote:
> > > Maynard Johnson wrote:
> > > > Hello,
> > > > I recently pulled down the systemtap src onto a Fedora 10 system and 
> > > > tried to use the itrace
> > > > probe point.  The resulting kernel module failed to compile because
> > > the runtime/itrace.c file
> > > > had not been updated to reflect the recent utrace interface changes.
> > > This problem had not
> > > > been caught because the itrace test is currently disabled (since it
> > > fails on x86_64).
> > >
> > > I looked at your changes a bit.  In remove_usr_itrace_info(), you
> > > probably need to ignore EALREADY (which means the DEATH callback has
> > > already begun so there is no point in detaching).
[snip]
> diff -paur systemtap-orig/runtime/itrace.c systemtap-fixes/runtime/itrace.c
> --- systemtap-orig/runtime/itrace.c	2009-03-03 15:45:40.000000000 -0500
> +++ systemtap-fixes/runtime/itrace.c	2009-03-03 15:49:14.000000000 -0500
> @@ -1,6 +1,6 @@
> @@ -232,7 +316,11 @@ void static remove_usr_itrace_info(struc
>
>  	spin_lock(&itrace_lock);
>  	if (ui->tsk && ui->engine) {
> -		(void) utrace_detach(ui->tsk, ui->engine);
> +		status = utrace_control(ui->tsk, ui->engine, UTRACE_DETACH);
> +		if (status < 0 && ((status != -ESRCH) || (status != -EALREADY)))
> +			printk(KERN_ERR
> +			       "utrace_control(UTRACE_DETACH) returns %d\n",
> +			       status);
>  	}
[snip]
Stupid logic error.  The line above should be:
	if (status < 0 && status != -ESRCH && status != -EALREADY)

-Maynard
> > >