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-rw-r--r--include/linux/tracepoint.h10
-rw-r--r--kernel/trace/bpf_trace.c3
-rw-r--r--kernel/tracepoint.c33
3 files changed, 42 insertions, 4 deletions
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 13f65420f188..ab58696d0ddd 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -41,7 +41,17 @@ extern int
tracepoint_probe_register_prio(struct tracepoint *tp, void *probe, void *data,
int prio);
extern int
+tracepoint_probe_register_prio_may_exist(struct tracepoint *tp, void *probe, void *data,
+ int prio);
+extern int
tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data);
+static inline int
+tracepoint_probe_register_may_exist(struct tracepoint *tp, void *probe,
+ void *data)
+{
+ return tracepoint_probe_register_prio_may_exist(tp, probe, data,
+ TRACEPOINT_DEFAULT_PRIO);
+}
extern void
for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
void *priv);
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 7a52bc172841..f0568b3d6bd1 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1840,7 +1840,8 @@ static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *
if (prog->aux->max_tp_access > btp->writable_size)
return -EINVAL;
- return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog);
+ return tracepoint_probe_register_may_exist(tp, (void *)btp->bpf_func,
+ prog);
}
int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 9f478d29b926..976bf8ce8039 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -273,7 +273,8 @@ static void tracepoint_update_call(struct tracepoint *tp, struct tracepoint_func
* Add the probe function to a tracepoint.
*/
static int tracepoint_add_func(struct tracepoint *tp,
- struct tracepoint_func *func, int prio)
+ struct tracepoint_func *func, int prio,
+ bool warn)
{
struct tracepoint_func *old, *tp_funcs;
int ret;
@@ -288,7 +289,7 @@ static int tracepoint_add_func(struct tracepoint *tp,
lockdep_is_held(&tracepoints_mutex));
old = func_add(&tp_funcs, func, prio);
if (IS_ERR(old)) {
- WARN_ON_ONCE(PTR_ERR(old) != -ENOMEM);
+ WARN_ON_ONCE(warn && PTR_ERR(old) != -ENOMEM);
return PTR_ERR(old);
}
@@ -344,6 +345,32 @@ static int tracepoint_remove_func(struct tracepoint *tp,
}
/**
+ * tracepoint_probe_register_prio_may_exist - Connect a probe to a tracepoint with priority
+ * @tp: tracepoint
+ * @probe: probe handler
+ * @data: tracepoint data
+ * @prio: priority of this function over other registered functions
+ *
+ * Same as tracepoint_probe_register_prio() except that it will not warn
+ * if the tracepoint is already registered.
+ */
+int tracepoint_probe_register_prio_may_exist(struct tracepoint *tp, void *probe,
+ void *data, int prio)
+{
+ struct tracepoint_func tp_func;
+ int ret;
+
+ mutex_lock(&tracepoints_mutex);
+ tp_func.func = probe;
+ tp_func.data = data;
+ tp_func.prio = prio;
+ ret = tracepoint_add_func(tp, &tp_func, prio, false);
+ mutex_unlock(&tracepoints_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(tracepoint_probe_register_prio_may_exist);
+
+/**
* tracepoint_probe_register_prio - Connect a probe to a tracepoint with priority
* @tp: tracepoint
* @probe: probe handler
@@ -366,7 +393,7 @@ int tracepoint_probe_register_prio(struct tracepoint *tp, void *probe,
tp_func.func = probe;
tp_func.data = data;
tp_func.prio = prio;
- ret = tracepoint_add_func(tp, &tp_func, prio);
+ ret = tracepoint_add_func(tp, &tp_func, prio, true);
mutex_unlock(&tracepoints_mutex);
return ret;
}