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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2014-02-26 18:37:38 (GMT)
committerSteven Rostedt <rostedt@goodmis.org>2014-03-04 02:11:05 (GMT)
commit45ab2813d40d88fc575e753c38478de242d03f88 (patch)
tree1859b05c3be128fd1c0a97c09c2fade4ad91e2e2
parent0414855fdc4a40da05221fc6062cccbc0c30f169 (diff)
downloadlinux-45ab2813d40d88fc575e753c38478de242d03f88.tar.xz
tracing: Do not add event files for modules that fail tracepoints
If a module fails to add its tracepoints due to module tainting, do not create the module event infrastructure in the debugfs directory. As the events will not work and worse yet, they will silently fail, making the user wonder why the events they enable do not display anything. Having a warning on module load and the events not visible to the users will make the cause of the problem much clearer. Link: http://lkml.kernel.org/r/20140227154923.265882695@goodmis.org Fixes: 6d723736e472 "tracing/events: add support for modules to TRACE_EVENT" Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: stable@vger.kernel.org # 2.6.31+ Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r--include/linux/tracepoint.h6
-rw-r--r--kernel/trace/trace_events.c10
-rw-r--r--kernel/tracepoint.c7
3 files changed, 22 insertions, 1 deletions
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index accc497..7159a0a 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -60,6 +60,12 @@ struct tp_module {
unsigned int num_tracepoints;
struct tracepoint * const *tracepoints_ptrs;
};
+bool trace_module_has_bad_taint(struct module *mod);
+#else
+static inline bool trace_module_has_bad_taint(struct module *mod)
+{
+ return false;
+}
#endif /* CONFIG_MODULES */
struct tracepoint_iter {
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index e71ffd4..f3989ce 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1777,6 +1777,16 @@ static void trace_module_add_events(struct module *mod)
{
struct ftrace_event_call **call, **start, **end;
+ if (!mod->num_trace_events)
+ return;
+
+ /* Don't add infrastructure for mods without tracepoints */
+ if (trace_module_has_bad_taint(mod)) {
+ pr_err("%s: module has bad taint, not creating trace events\n",
+ mod->name);
+ return;
+ }
+
start = mod->trace_events;
end = mod->trace_events + mod->num_trace_events;
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 29f2654..031cc56 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -631,6 +631,11 @@ void tracepoint_iter_reset(struct tracepoint_iter *iter)
EXPORT_SYMBOL_GPL(tracepoint_iter_reset);
#ifdef CONFIG_MODULES
+bool trace_module_has_bad_taint(struct module *mod)
+{
+ return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP));
+}
+
static int tracepoint_module_coming(struct module *mod)
{
struct tp_module *tp_mod, *iter;
@@ -641,7 +646,7 @@ 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 (trace_module_has_bad_taint(mod))
return 0;
mutex_lock(&tracepoints_mutex);
tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL);