tracepoints/module: Fix disabling tracepoints with taint CRAP or OOT

Tracepoints are disabled for tainted modules, which is usually because the
module is either proprietary or was forced, and we don't want either of them
using kernel tracepoints.

But, a module can also be tainted by being in the staging directory or
compiled out of tree. Either is fine for use with tracepoints, no need
to punish them.  I found this out when I noticed that my sample trace event
module, when done out of tree, stopped working.

Cc: stable@vger.kernel.org # 3.2
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Dave Jones <davej@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index db110b8..f1539de 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -634,10 +634,11 @@ static int tracepoint_module_coming(struct module *mod)
 	int ret = 0;
 
 	/*
-	 * We skip modules that tain the kernel, especially those with different
-	 * module header (for forced load), to make sure we don't cause a crash.
+	 * We skip modules that taint the kernel, especially those with different
+	 * module headers (for forced load), to make sure we don't cause a crash.
+	 * Staging and out-of-tree GPL modules are fine.
 	 */
-	if (mod->taints)
+	if (mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP)))
 		return 0;
 	mutex_lock(&tracepoints_mutex);
 	tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL);