[RFC][PATCH] tracing: Warn and notify if tracepoints are not loaded due to module taint

[Steven Rostedt]

[ Posting this as an RFC, but I plan on pushing it as soon as I finish
testing it ]

If a module is loaded that is tainted with anything but OOT or CRAP, then
it will not create the traceoint infrastructure for the module. There should
be a big warning when this happens instead of exiting silently.

Fixes: 97e1c18e8d17 "tracing: Kernel Tracepoints"
Cc: stable@xxxxxxxxxxxxxxx
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 kernel/tracepoint.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 29f2654..413bc06 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -641,7 +641,8 @@ static int tracepoint_module_coming(struct module *mod)
 	 * 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 & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP)))
+	if (WARN_ONCE(mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP)),
+		      "Module is tainted, disabling tracepoints"))
 		return 0;
 	mutex_lock(&tracepoints_mutex);
 	tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL);
-- 
1.8.5.3

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