The q->id is used as an index within the blkg_tree radix tree.
If the entry is not released before reclaiming the blk_queue_ida's id
blkcg_init_queue() within a different driver from which this id
was originally for can fail due to the entry at that index within
the radix tree already existing.
Signed-off-by: Alexandru Moise <00moses.alexander00@xxxxxxxxx>
---
v2: Added no-op for !CONFIG_BLK_CGROUP
block/blk-cgroup.c | 2 +-
block/blk-sysfs.c | 4 ++++
include/linux/blk-cgroup.h | 3 +++
3 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 1c16694ae145..224e937dbb59 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -369,7 +369,7 @@ static void blkg_destroy(struct blkcg_gq *blkg)
*
* Destroy all blkgs associated with @q.
*/
-static void blkg_destroy_all(struct request_queue *q)
+void blkg_destroy_all(struct request_queue *q)
{
struct blkcg_gq *blkg, *n;
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index d00d1b0ec109..a72866458f22 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -816,6 +816,10 @@ static void __blk_release_queue(struct work_struct *work)
if (q->bio_split)
bioset_free(q->bio_split);
+ spin_lock_irq(q->queue_lock);
+ blkg_destroy_all(q);
+ spin_unlock_irq(q->queue_lock);
+
ida_simple_remove(&blk_queue_ida, q->id);
call_rcu(&q->rcu_head, blk_free_queue_rcu);
}
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 6c666fd7de3c..3d60b1d1973d 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -179,6 +179,8 @@ struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
int blkcg_init_queue(struct request_queue *q);
void blkcg_drain_queue(struct request_queue *q);
void blkcg_exit_queue(struct request_queue *q);
+void blkg_destroy_all(struct request_queue *q);
+
/* Blkio controller policy registration */
int blkcg_policy_register(struct blkcg_policy *pol);
@@ -740,6 +742,7 @@ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { ret
static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
static inline void blkcg_drain_queue(struct request_queue *q) { }
static inline void blkcg_exit_queue(struct request_queue *q) { }
+static inline void blkg_destroy_all(struct request_queue *q) { }
static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
static inline int blkcg_activate_policy(struct request_queue *q,
--
2.16.2
