The initialization of partition's percpu_ref should have been done before the new partition is updated to partition table via rcu_assign_pointer(), otherwise the uninitialized percpu_ref may be accessed in data path.
This patch fixes this issue reported by Naveen. Reported-by: Naveen Kaje <[email protected]> Tested-by: Naveen Kaje <[email protected]> Fixes: 6c71013ecb7e2(block: partition: convert percpu ref) Cc: <[email protected]> # v4.3+ Signed-off-by: Ming Lei <[email protected]> --- V1: - put 'if' around the actual device_remove_file at the label as suggested by Christoph - make commit log more accurate block/partition-generic.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/block/partition-generic.c b/block/partition-generic.c index 5d87019..54d4be8 100644 --- a/block/partition-generic.c +++ b/block/partition-generic.c @@ -361,15 +361,17 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno, goto out_del; } + err = hd_ref_init(p); + if (err) + goto out_remove_file; + /* everything is up and running, commence */ rcu_assign_pointer(ptbl->part[partno], p); /* suppress uevent if the disk suppresses it */ if (!dev_get_uevent_suppress(ddev)) kobject_uevent(&pdev->kobj, KOBJ_ADD); - - if (!hd_ref_init(p)) - return p; + return p; out_free_info: free_part_info(p); @@ -378,6 +380,9 @@ out_free_stats: out_free: kfree(p); return ERR_PTR(err); +out_remove_file: + if (flags & ADDPART_FLAG_WHOLEDISK) + device_remove_file(pdev, &dev_attr_whole_disk); out_del: kobject_put(p->holder_dir); device_del(pdev); -- 1.9.1
