Re: [PATCH] sched: fix string comparison in features

Mathieu Desnoyers
2010-09-13T21:40:06Z

* Steven Rostedt (rostedt@goodmis.org) wrote:
> On Sat, 2010-09-11 at 13:44 -0400, Mathieu Desnoyers wrote:
> > Incorrect handling of the following case:
> >
> > INTERACTIVE
> > INTERACTIVE_SOMETHING_ELSE
> >
> > The comparison only checks up to each element's length.
>
> Replace all your changes with mine, and you have the same effect ;-)

Indeed, your approach looks much nicer. Will update.

Thanks,

Mathieu

>
> -- Steve
>
> >
> > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> > ---
> > kernel/sched.c | 11 ++++++++++-
> > 1 file changed, 10 insertions(+), 1 deletion(-)
> >
> > Index: linux-2.6-lttng.git/kernel/sched.c
> > ===================================================================
> > --- linux-2.6-lttng.git.orig/kernel/sched.c
> > +++ linux-2.6-lttng.git/kernel/sched.c
> > @@ -722,7 +722,7 @@ sched_feat_write(struct file *filp, cons
> > {
> > char buf[64];
> > char *cmp = buf;
>
> - char *cmp = buf;
> + char *cmp;
>
> > - int neg = 0;
> > + int neg = 0, cmplen;
> > int i;
> >
> > if (cnt > 63)
> > @@ -732,15 +732,24 @@ sched_feat_write(struct file *filp, cons
> > return -EFAULT;
> >
> > buf[cnt] = 0;
> > + for (i = 0; i < cnt; i++) {
> > + if (buf[i] == '\n' || buf[i] == ' ') {
> > + buf[i] = 0;
> > + break;
> > + }
> > + }
>
> + cmp = strstrip(buf);
>
> >
> > if (strncmp(buf, "NO_", 3) == 0) {
> > neg = 1;
> > cmp += 3;
> > }
> >
> > + cmplen = strlen(cmp);
> > for (i = 0; sched_feat_names[i]; i++) {
> > int len = strlen(sched_feat_names[i]);
>
> - int len = strlen(sched_feat_names[i]);
>
> >
> > + if (cmplen != len)
> > + continue;
> > if (strncmp(cmp, sched_feat_names[i], len) == 0) {
>
> - if (strncmp(cmp, sched_feat_names[i], len) == 0) {
> + if (strcmp(cmp, sched_feat_names[i]) == 0) {
>
> > if (neg)
> > sysctl_sched_features &= ~(1UL << i);
>
>

--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.