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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-05-03 20:38:55 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-06-09 03:52:31 +0200 |
| commit | fa3c66476975abf00c97f27b6c2b3d223f7d57f5 (patch) | |
| tree | 3f39de6eb3438f8910e5a40fda19e79fd4813689 | |
| parent | rcu: Remove linux/debugobjects.h from rcupdate.h (diff) | |
| download | linux-fa3c66476975abf00c97f27b6c2b3d223f7d57f5.tar.xz linux-fa3c66476975abf00c97f27b6c2b3d223f7d57f5.zip | |
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@oracle.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| -rw-r--r-- | kernel/rcu/tree.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 61a97164abcc..cac24f5d3fd2 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; |