5.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
commit d1248436cbef1f924c04255367ff4845ccd9025e upstream.
blkcg_fill_root_iostats() iterates over @block_class's devices by
class_dev_iter_(init|next)(), but does not end iterating with
class_dev_iter_exit(), so causes the class's subsystem refcount leakage.
Fix by ending the iterating with class_dev_iter_exit().
Fixes: ef45fe470e1e ("blk-cgroup: show global disk stats in root cgroup io.stat")
Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20250105-class_fix-v6-2-3a2f1768d4d4@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-cgroup.c | 1 +
1 file changed, 1 insertion(+)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -851,6 +851,7 @@ static void blkcg_fill_root_iostats(void
}
disk_put_part(part);
}
+ class_dev_iter_exit(&iter);
}
static int blkcg_print_stat(struct seq_file *sf, void *v)
