Re: [PATCH] tracing: fix event_subsystem ref counting

From: Steven Rostedt
Date: Mon Oct 31 2011 - 12:15:10 EST


On Mon, 2011-10-31 at 11:07 +0200, Ilya Dryomov wrote:
> Fix a bug introduced by e9dbfae5, which prevents event_subsystem from
> ever being released.
>
> Ref_count was added to keep track of subsystem users, not for counting
> events. Subsystem is created with ref_count = 1, so there is no need to
> increment it for every event, we have nr_events for that. Fix this by
> touching ref_count only when we actually have a new user -
> subsystem_open().

Good catch, I'll pull this in.

Thanks!

-- Steve

>
> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
> ---
> kernel/trace/trace_events.c | 1 -
> 1 files changed, 0 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index 581876f..c212a7f 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -1078,7 +1078,6 @@ event_subsystem_dir(const char *name, struct dentry *d_events)
> /* First see if we did not already create this dir */
> list_for_each_entry(system, &event_subsystems, list) {
> if (strcmp(system->name, name) == 0) {
> - __get_system(system);
> system->nr_events++;
> return system->entry;
> }


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