lkml.org 
[lkml]   [2017]   [Oct]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v3 12/33] tracing: Add variable support to hist triggers
Hi Tom,

On Wed, Oct 11, 2017 at 08:33:17AM -0500, Tom Zanussi wrote:
> On Mon, 2017-10-09 at 12:27 +0900, Namhyung Kim wrote:
> > On Fri, Sep 22, 2017 at 02:59:52PM -0500, Tom Zanussi wrote:
> > > Variables set as above can be used by being referenced from another
> > > event, as described in a subsequent patch.
> >
> > That means, a variable should be unique (in a tracing instance at least).
> >
>
> Not exactly - I thought it would be too restrictive to force users to
> come up with names that would be unique across an instance, so made them
> unique to events. So users can use the same variable name for triggers
> on multiple events, and in cases where there are multiple events with
> the same name, use the fully-qualified subsys.event_name.variable_name
> name to disambiguate them. If there is only one event with the given
> name, thus no ambiguity, specifying the bare variable name suffices.
> Again the intent is to make the common case as simple as possible, but
> allow for more complex cases without requiring naming gymnastics from
> the user.

Agreed. Thanks for the explanation.


[SNIP]

> > > +static int parse_var_defs(struct hist_trigger_data *hist_data)
> > > +{
> > > + char *s, *str, *var_name, *field_str;
> > > + unsigned int i, j, n_vars = 0;
> > > + int ret = 0;
> > > +
> > > + for (i = 0; i < hist_data->attrs->n_assignments; i++) {
> > > + str = hist_data->attrs->assignment_str[i];
> > > + for (j = 0; j < TRACING_MAP_VARS_MAX; j++) {
> > > + field_str = strsep(&str, ",");
> > > + if (!field_str)
> > > + break;
> > > +
> > > + var_name = strsep(&field_str, "=");
> > > + if (!var_name || !field_str) {
> > > + ret = -EINVAL;
> > > + goto free;
> > > + }
> > > +
> > > + s = kstrdup(var_name, GFP_KERNEL);
> > > + if (!s) {
> > > + ret = -ENOMEM;
> > > + goto free;
> > > + }
> > > + hist_data->attrs->var_defs.name[n_vars] = s;
> > > +
> > > + s = kstrdup(field_str, GFP_KERNEL);
> > > + if (!s) {
> > > + ret = -ENOMEM;
> > > + goto free;
> >
> > It seems that it might leak the copy of var_name here..
> >
>
> Unless I'm missing something, the free_var_defs() should handle this
> case too...

But the var_defs.n_vars was not increased at this point.

Thanks,
Namhyung


> >
> > > + }
> > > + hist_data->attrs->var_defs.expr[n_vars++] = s;
> > > +
> > > + hist_data->attrs->var_defs.n_vars = n_vars;
> > > +
> > > + if (n_vars == TRACING_MAP_VARS_MAX)
> > > + goto free;
> > > + }
> > > + }
> > > +
> > > + return ret;
> > > + free:
> > > + free_var_defs(hist_data);
> > > +
> > > + return ret;
> > > +}
> > > +
>
>

\
 
 \ /
  Last update: 2017-10-12 01:24    [W:0.079 / U:12.152 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site