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-rw-r--r--kernel/rcu.h10
-rw-r--r--kernel/rcutree.c14
2 files changed, 20 insertions, 4 deletions
diff --git a/kernel/rcu.h b/kernel/rcu.h
index 0a90ccc65bfb..77131966c4ad 100644
--- a/kernel/rcu.h
+++ b/kernel/rcu.h
@@ -67,12 +67,15 @@
extern struct debug_obj_descr rcuhead_debug_descr;
-static inline void debug_rcu_head_queue(struct rcu_head *head)
+static inline int debug_rcu_head_queue(struct rcu_head *head)
{
- debug_object_activate(head, &rcuhead_debug_descr);
+ int r1;
+
+ r1 = debug_object_activate(head, &rcuhead_debug_descr);
debug_object_active_state(head, &rcuhead_debug_descr,
STATE_RCU_HEAD_READY,
STATE_RCU_HEAD_QUEUED);
+ return r1;
}
static inline void debug_rcu_head_unqueue(struct rcu_head *head)
@@ -83,8 +86,9 @@ static inline void debug_rcu_head_unqueue(struct rcu_head *head)
debug_object_deactivate(head, &rcuhead_debug_descr);
}
#else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
-static inline void debug_rcu_head_queue(struct rcu_head *head)
+static inline int debug_rcu_head_queue(struct rcu_head *head)
{
+ return 0;
}
static inline void debug_rcu_head_unqueue(struct rcu_head *head)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index a7bf517b0482..91840566e294 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -2305,6 +2305,13 @@ static void __call_rcu_core(struct rcu_state *rsp, struct rcu_data *rdp,
}
/*
+ * RCU callback function to leak a callback.
+ */
+static void rcu_leak_callback(struct rcu_head *rhp)
+{
+}
+
+/*
* Helper function for call_rcu() and friends. The cpu argument will
* normally be -1, indicating "currently running CPU". It may specify
* a CPU only if that CPU is a no-CBs CPU. Currently, only _rcu_barrier()
@@ -2318,7 +2325,12 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
struct rcu_data *rdp;
WARN_ON_ONCE((unsigned long)head & 0x3); /* Misaligned rcu_head! */
- debug_rcu_head_queue(head);
+ if (debug_rcu_head_queue(head)) {
+ /* Probable double call_rcu(), so leak the callback. */
+ ACCESS_ONCE(head->func) = rcu_leak_callback;
+ WARN_ONCE(1, "__call_rcu(): Leaked duplicate callback\n");
+ return;
+ }
head->func = func;
head->next = NULL;