Commit-ID: a4f4bb6d0c69d0bb573f1d9e6f1b806f9b038b19 Gitweb: http://git.kernel.org/tip/a4f4bb6d0c69d0bb573f1d9e6f1b806f9b038b19 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Wed, 24 Feb 2016 18:45:42 +0100 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 25 Feb 2016 08:42:33 +0100
perf: Allow perf_release() with !event->ctx In the err_file: fput(event_file) case, the event will not yet have been attached to a context. However perf_release() does assume it has been. Cure this. Tested-by: Alexander Shishkin <alexander.shish...@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Reviewed-by: Alexander Shishkin <alexander.shish...@linux.intel.com> Cc: Arnaldo Carvalho de Melo <a...@redhat.com> Cc: Jiri Olsa <jo...@redhat.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: dvyu...@google.com Cc: eran...@google.com Cc: o...@redhat.com Cc: pan...@redhat.com Cc: sasha.le...@oracle.com Cc: vi...@deater.net Link: http://lkml.kernel.org/r/20160224174947.793996...@infradead.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/events/core.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 211a5ce..d5299e2 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3754,9 +3754,19 @@ static void put_event(struct perf_event *event) */ int perf_event_release_kernel(struct perf_event *event) { - struct perf_event_context *ctx; + struct perf_event_context *ctx = event->ctx; struct perf_event *child, *tmp; + /* + * If we got here through err_file: fput(event_file); we will not have + * attached to a context yet. + */ + if (!ctx) { + WARN_ON_ONCE(event->attach_state & + (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); + goto no_ctx; + } + if (!is_kernel_event(event)) perf_remove_from_owner(event); @@ -3832,8 +3842,8 @@ again: } mutex_unlock(&event->child_mutex); - /* Must be the last reference */ - put_event(event); +no_ctx: + put_event(event); /* Must be the 'last' reference */ return 0; } EXPORT_SYMBOL_GPL(perf_event_release_kernel);
