diff options
| author | Paul E. McKenney <paulmck@kernel.org> | 2020-12-08 13:45:49 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-01-22 15:24:16 -0800 |
| commit | b4b7914a6a73fc169fd1ce2fcd78a1d83d9528a9 (patch) | |
| tree | f11dec127204fc013b14c97745741b27e7141fb1 | |
| parent | bd34dcd4120d7e358baac9c22ef1321bd0c22079 (diff) | |
rcu: Make call_rcu() print mem_dump_obj() info for double-freed callback
The debug-object double-free checks in __call_rcu() print out the
RCU callback function, which is usually sufficient to track down the
double free. However, all uses of things like queue_rcu_work() will
have the same RCU callback function (rcu_work_rcufn() in this case),
so a diagnostic message for a double queue_rcu_work() needs more than
just the callback function.
This commit therefore calls mem_dump_obj() to dump out any additional
available information on the double-freed callback.
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
| -rw-r--r-- | kernel/rcu/tree.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 40e5e3dd253e..84513c52d9b0 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2941,6 +2941,7 @@ static void check_cb_ovld(struct rcu_data *rdp) static void __call_rcu(struct rcu_head *head, rcu_callback_t func) { + static atomic_t doublefrees; unsigned long flags; struct rcu_data *rdp; bool was_alldone; @@ -2954,8 +2955,10 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func) * 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->%pS()!!!\n", - head, head->func); + if (atomic_inc_return(&doublefrees) < 4) { + pr_err("%s(): Double-freed CB %p->%pS()!!! ", __func__, head, head->func); + mem_dump_obj(head); + } WRITE_ONCE(head->func, rcu_leak_callback); return; } |