Commit-ID: fa3c66476975abf00c97f27b6c2b3d223f7d57f5
Gitweb: http://git.kernel.org/tip/fa3c66476975abf00c97f27b6c2b3d223f7d57f5
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Wed, 3 May 2017 11:38:55 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Thu, 8 Jun 2017 18:52:31 -0700
rcu: Improve __call_rcu() debug-objects error message
The "__call_rcu(): Leaked duplicate callback" error message from
__call_rcu() has proven to be unhelpful. This commit therefore changes
it to "__call_rcu(): Double-freed CB" and adds the value of the pointer
passed in. The value of the pointer improves debuggability by allowing
correlation with tracing output, for example, the rcu:rcu_callback trace
event.
Reported-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 61a9716..cac24f5 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3161,9 +3161,14 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func,
WARN_ON_ONCE((unsigned long)head & (sizeof(void *) - 1));
if (debug_rcu_head_queue(head)) {
- /* Probable double call_rcu(), so leak the callback. */
+ /*
+ * Probable double call_rcu(), so leak the callback.
+ * Use rcu:rcu_callback trace event to find the previous
+ * time callback was passed to __call_rcu().
+ */
+ WARN_ONCE(1, "__call_rcu(): Double-freed CB %p->%pF()!!!\n",
+ head, head->func);
WRITE_ONCE(head->func, rcu_leak_callback);
- WARN_ONCE(1, "__call_rcu(): Leaked duplicate callback\n");
return;
}
head->func = func;
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|