On Mon, 2013-04-15 at 11:13 +0900, kpark3...@gmail.com wrote:
> From: Sahara <keun-o.p...@windriver.com>
>
> Somehow tracepoint_entry_add_probe function allows a null probe function.
> And, this may lead to unexpected result since the number of probe
> functions in an entry can be counted by checking whether probe is null
> or not in for-loop.
> This patch prevents the null probe from being added.
> In tracepoint_entry_remove_probe function, checking probe parameter
> within for-loop is moved out for code efficiency leaving the null probe
> feature which removes all probe functions in the entry.
>
> Signed-off-by: Sahara <keun-o.p...@windriver.com>
> Reviewed-by: Steven Rostedt <rost...@goodmis.org>
> Reviewed-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
BTW, do not add tags that were not given to you. "Reviewed-by" has a
meaning, more than just someone that reviewed your patch. It means that
they not only reviewed your patch but couldn't find anything wrong with
it. As both Mathieu and I had comments, that does not deserve a
"Reviewed-by" tag.
I'm not even sure that Mathieu gave an "Acked-by". I thought he did, but
I can't seem to find it. Mathieu?
Anyway, I'll start testing this patch as it seems fine with me (although
I still wouldn't give a Reviewed-by tag).
Thanks,
-- Steve
> ---
> kernel/tracepoint.c | 21 +++++++++++++--------
> 1 files changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
> index 0c05a45..29f2654 100644
> --- a/kernel/tracepoint.c
> +++ b/kernel/tracepoint.c
> @@ -112,7 +112,8 @@ tracepoint_entry_add_probe(struct tracepoint_entry *entry,
> int nr_probes = 0;
> struct tracepoint_func *old, *new;
>
> - WARN_ON(!probe);
> + if (WARN_ON(!probe))
> + return ERR_PTR(-EINVAL);
>
> debug_print_probes(entry);
> old = entry->funcs;
> @@ -152,13 +153,18 @@ tracepoint_entry_remove_probe(struct tracepoint_entry
> *entry,
>
> debug_print_probes(entry);
> /* (N -> M), (N > 1, M >= 0) probes */
> - for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
> - if (!probe ||
> - (old[nr_probes].func == probe &&
> - old[nr_probes].data == data))
> - nr_del++;
> + if (probe) {
> + for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
> + if (old[nr_probes].func == probe &&
> + old[nr_probes].data == data)
> + nr_del++;
> + }
> }
>
> + /*
> + * If probe is NULL, then nr_probes = nr_del = 0, and then the
> + * entire entry will be removed.
> + */
> if (nr_probes - nr_del == 0) {
> /* N -> 0, (N > 1) */
> entry->funcs = NULL;
> @@ -173,8 +179,7 @@ tracepoint_entry_remove_probe(struct tracepoint_entry
> *entry,
> if (new == NULL)
> return ERR_PTR(-ENOMEM);
> for (i = 0; old[i].func; i++)
> - if (probe &&
> - (old[i].func != probe || old[i].data != data))
> + if (old[i].func != probe || old[i].data != data)
> new[j++] = old[i];
> new[nr_probes - nr_del].func = NULL;
> entry->refcount = nr_probes - nr_del;
--
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