Commit-ID: a602538e46c9c62e75f1f0be9806495c79bcda9f
Gitweb: http://git.kernel.org/tip/a602538e46c9c62e75f1f0be9806495c79bcda9f
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Fri, 28 Apr 2017 15:39:34 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Thu, 8 Jun 2017 08:25:39 -0700
srcu: Add DEBUG_OBJECTS_RCU_HEAD functionality
This commit adds DEBUG_OBJECTS_RCU_HEAD checking to detect call_srcu()
counterparts to double-free bugs.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/srcutree.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 0b6ea10..c6e2a4a 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -762,6 +762,13 @@ static bool srcu_might_be_idle(struct srcu_struct *sp)
}
/*
+ * SRCU callback function to leak a callback.
+ */
+static void srcu_leak_callback(struct rcu_head *rhp)
+{
+}
+
+/*
* Enqueue an SRCU callback on the srcu_data structure associated with
* the current CPU and the specified srcu_struct structure, initiating
* grace-period processing if it is not already running.
@@ -799,6 +806,12 @@ void __call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,
struct srcu_data *sdp;
check_init_srcu_struct(sp);
+ if (debug_rcu_head_queue(rhp)) {
+ /* Probable double call_srcu(), so leak the callback. */
+ WRITE_ONCE(rhp->func, srcu_leak_callback);
+ WARN_ONCE(1, "call_srcu(): Leaked duplicate callback\n");
+ return;
+ }
rhp->func = func;
local_irq_save(flags);
sdp = this_cpu_ptr(sp->sda);
@@ -973,9 +986,12 @@ void srcu_barrier(struct srcu_struct *sp)
spin_lock_irq(&sdp->lock);
atomic_inc(&sp->srcu_barrier_cpu_cnt);
sdp->srcu_barrier_head.func = srcu_barrier_cb;
+ debug_rcu_head_queue(&sdp->srcu_barrier_head);
if (!rcu_segcblist_entrain(&sdp->srcu_cblist,
- &sdp->srcu_barrier_head, 0))
+ &sdp->srcu_barrier_head, 0)) {
+ debug_rcu_head_unqueue(&sdp->srcu_barrier_head);
atomic_dec(&sp->srcu_barrier_cpu_cnt);
+ }
spin_unlock_irq(&sdp->lock);
}
@@ -1100,6 +1116,7 @@ static void srcu_invoke_callbacks(struct work_struct *work)
spin_unlock_irq(&sdp->lock);
rhp = rcu_cblist_dequeue(&ready_cbs);
for (; rhp != NULL; rhp = rcu_cblist_dequeue(&ready_cbs)) {
+ debug_rcu_head_unqueue(rhp);
local_bh_disable();
rhp->func(rhp);
local_bh_enable();
--
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
|